When two layers of graphene are stacked with a twist angle of approximately 1.1°,strong interlayer coupling gives rise to a pair of flat bands in twisted bilayer graphene(TBG),resulting in pronounced electron–el...When two layers of graphene are stacked with a twist angle of approximately 1.1°,strong interlayer coupling gives rise to a pair of flat bands in twisted bilayer graphene(TBG),resulting in pronounced electron–electron interactions.At half filling of the flat bands,TBG exhibits correlated insulating states.Here,we investigate the electrical transport properties of heterostructures composed of TBG and the antiferromagnetic insulator chromium oxychloride(CrOCl),and propose a strategy to modulate the correlated insulating states in TBG.During the transition from a conventional phase to a strong interfacial coupling phase,kink-like features are observed in the charge neutrality point(CNP),correlated insulating state,and band insulating state.Under a perpendicular magnetic field,the system exhibits broadened quantum Hall plateaus in the strong interfacial coupling regime.Electrons localized in the CrOCl layer screen the bottom gate,rendering the carrier density in TBG less sensitive to variations in the bottom gate voltage.These phenomena are well captured by a charge-transfer model between TBG and CrOCl.Our results provide insights into the control of electronic correlations and topological states in graphene moirésystems via interfacial charge coupling.展开更多
In this study,we developed a novel bilayered scaffold consisting of a bottom layer composed of the Decellularized Bovine Pericardium(DP)coated with Polyaniline Nanoparticles(PANINPs)and a top layer made of an electros...In this study,we developed a novel bilayered scaffold consisting of a bottom layer composed of the Decellularized Bovine Pericardium(DP)coated with Polyaniline Nanoparticles(PANINPs)and a top layer made of an electrospun Poly(lactic-co-glycolic acid)/Gelatin(PLGA/Gel)membrane incorporated with Vascular Endothelial Growth Fac-tor(VEGF)and hawthorn extract.Functionally,the DP supplies native Extracellular Matrix(ECM)components and mechanical support,while PANINPs provide conductivity.The electrospun PLGA/Gel layer mimics fibrous ECM.It incorporates bioactives,with VEGF promoting pro-angiogenic stimulation and hawthorn extract enhanc-ing anticoagulant activity,as well as increasing surface hydrophilicity.The tissue adhesive ensures the interfacial integrity between the two layers.Decellularization efficiency was confirmed histologically using 4',6-diamidino-2-phenylindole(DAPI)and Hematoxylin-Eosin(H&E)staining.The DP exhibited a DNA content of 115.9±47.8 ng/mg DNA,compared to 982.88±395.42 ng/mg in Native Pericardium(NP).The PANINPs had an average par-ticle size of 104.94±13.7 nm.The conductivity of PANINPs-coated decellularized pericardium was measured to be 9.093±8.6×10-4 S/cm using the four-point probe method.PLGA/Gel membranes containing hawthorn extract(1%,5%,10%,and 15%w/v)and VEGF(0.1μg/mL,0.5μg/mL,and 1μg/mL)were fabricated by electrospinning,result-ing in fiber diameters between 850 and 1200 nm and pore sizes between 14 and 20μm.The anticoagulant efficiency of the membranes containing hawthorn extract reached 430 s in the Activated Partial Thromboplastin Time Assay(aPTT).Mechanical testing revealed a tensile strength of 22.70±6.33 MPa,an elongation of 53.58±10.63%,and Young's modulus of 0.67±0.10 MPa.The scaffold also exhibited over 91%cell viability and excellent cardiomyo-cyte adhesion.The hemolysis ratio was determined to be 0.421±0.191%,which confirms its blood compatibility.Our results indicate that the proposed bilayered scaffold can be a promising candidate for cardiac patch applications.展开更多
This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the pre...This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the prepared surfaces are placed on top of each other and by rolling with reduction more than 50%,the bonding between layers is established.In this research,the roll bonding process was done at room temperature,without the use of lubricants and with a 70%thickness reduction.Then,the final thickness of the Ag/Al bilayer sheet reached 350μm by several stages of cold rolling.Before cold rolling,it should be noted that to decrease the hardness created due to plastic deformation,the roll-bonded samples were subjected to annealing heat treatment at 400℃for 90 min.Thus,the final samples were annealed at 200,300 and 400℃for 90 min and cooled in a furnace to examine the annealing temperature effects.The uniaxial tensile and microhardness tests measured mechanical properties.Also,to investigate the fracture mechanism,the fractography of the cross-section was examined by scanning electron microscope(SEM).To evaluate the formability of Ag/Al bilayer sheets,forming limit curves were obtained experimentally through the Nakazima test.The resistance of composites to failure due to cracking was also investigated by fracture toughness.The results showed that annealing increases the elongation and formability of the Ag/Al bilayer sheet while reduces the ultimate tensile strength and fracture toughness.However,the changing trend is not the same at different temperatures,and according to the results,the most significant effect is obtained at 300℃and aluminum layers.It was also determined that by increasing annealing temperature,the fracture mechanism from shear ductile with small and shallow dimples becomes ductile with deep cavities.展开更多
We investigate the energy bands,magnetism,and superconductivity of bilayer octagraphene with A-A stackingunder a perpendicular electric field.A tight-binding model is used to analyze the band structure of the system.T...We investigate the energy bands,magnetism,and superconductivity of bilayer octagraphene with A-A stackingunder a perpendicular electric field.A tight-binding model is used to analyze the band structure of the system.The doubling of the unit cell results in each band of the single layer splitting into two.We find that applyinga perpendicular electric field increases the band splitting.As the electric field strength increases,the nestingof the Fermi surface(FS)weakens,eventually disrupting the antiferromagnetic order,and bilayer octagrapheneexhibits superconductivity.Spin fluctuations can induce unconventional superconductivity with s±-wave pairing.Applying a perpendicular electric field to bilayer octagraphene parent weakens the nesting of the FS,ultimatelykilling the spin-density-wave(SDW)ordered state and transitioning it into the superconducting state,whichworks as a doping effect.We use the random-phase approximation approach to obtain the pairing eigenvaluesand pairing symmetries of the perpendicular electric field-tuned bilayer octagraphene in the weak coupling limit.By tuning the strength of the perpendicular electric field,the critical interaction strength for SDW order can bemodified,which in turn may promote the emergence of unconventional superconductivity.展开更多
This study demonstrates the successful fabrication of solid-state bilayers using LiFePO_(4)(LFP)cathodes and Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)-based Composite Solid Electrolytes(CSEs)via Cold Sintering Proces...This study demonstrates the successful fabrication of solid-state bilayers using LiFePO_(4)(LFP)cathodes and Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)-based Composite Solid Electrolytes(CSEs)via Cold Sintering Process(CSP).By optimizing the sintering pressure,it is achieved an intimate contact between the cathode and the solid electrolyte,leading to an enhanced electrochemical performance.Bilayers cold sintered at 300 MPa and a low-sintering temperature of 150℃exhibit high ionic conductivities(0.5 mS cm^(-1))and stable specific capacities at room temperature(160.1 mAh g^(-1)LFP at C/10 and 75.8 mAh g^(-1)_(LFP)at 1 C).Moreover,an operando electrochemical impedance spectroscopy(EIS)technique is employed to identify limiting factors of the bilayer kinetics and to anticipate the overall electrochemical behavior.Results suggest that capacity fading can occur in samples prepared with high sintering pressures due to a volume reduction in the LFP crystalline cell.This work demonstrates the potential of CSP to produce straightforward high-performance bilayers and introduces a valuable non-destructive instrument for understanding and avoiding degradation in solid-state lithium-based batteries.展开更多
We demonstrate that the sliding motion between two layers of the newly discovered ferroelectric and topologically trivial bismuth(Bi)monolayer[Nature 61767(2023)]can induce a sequence of topological phase transitions,...We demonstrate that the sliding motion between two layers of the newly discovered ferroelectric and topologically trivial bismuth(Bi)monolayer[Nature 61767(2023)]can induce a sequence of topological phase transitions,alternating between Z_(2)trivial and nontrivial states.The lateral shift,while preserving spatial symmetry,can switch the quantum spin Hall state on and of.The sliding-induced changes in out-of-plane atomic buckling,which are directly coupled to in-plane ferroelectricity,are shown to signifcantly modulate the band gap and drive the topological phase transitions.We map out the topological phase diagram and in-plane ferroelectricity with respect to sliding displacements.With appropriate sliding,the bismuth bilayer can transition into a nontrivial polar metal,exhibiting a pronounced shift current response arising from interband geometric quantities of electronic bands.Moreover,bilayer Bi supports a sliding-tunable nonlinear anomalous Hall response resulting from the geometric Berry curvature dipole.Confgurations that are Z_(2)nontrivial can generate drastically different transverse currents orthogonal to the external electric feld,as both the direction and magnitude of the Berry curvature dipole at the Fermi level are highly sensitive to the sliding displacement.Our results suggest that bilayer bismuth,with its ability to generate multiple types of geometric currents,ofers a versatile platform for power-efcient“Berry slidetronics”for multistate memory applications integrating both band topology and ferroelectricity.展开更多
Osteochondral defects pose an enormous challenge,and no satisfactory therapy is available to date due to the hierarchy of the native tissue consisting of articular cartilage and subchondral bone.Constructing a scaffol...Osteochondral defects pose an enormous challenge,and no satisfactory therapy is available to date due to the hierarchy of the native tissue consisting of articular cartilage and subchondral bone.Constructing a scaffold with biological function and biomimetic structure is the key to achieving a high-quality repair effect.Herein,a natural polymer-based bilayer scaffold with a porous architecture similar to that of osteochondral tissue is designed,involving the transforming growth factor-beta3-liposome-loaded upper layer for superficial cartilage regeneration and the nanohydroxyapatite-coated lower layer for subchondral bone rehabilitation.This research is conducted to evaluate the effects of nanoparticle-modified bilayer scaffold to mimic the hierarchical pro-chondrogenic and proosteogenic microenvironment for the recruited endogenous bone marrow mesenchymal stem cells.The fabricated composites were evaluated for mechanical,physicochemical,biological properties,in vitro and in vivo tissue regeneration potential.Overall,the current bilayer scaffold could regenerate a cartilage-bone integrated tissue with a seamless interfacial integration and exhibited superior tissue repair outcomes compared to other single layer scaffolds based on morphological,radiological and histological evaluation,verifying that this novel graft could be an effective approach to tissue-engineered analogs of cartilage-subchondral bone and offer new therapeutic opportunities for osteochondral defect-associated diseases.展开更多
Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical...Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.展开更多
Sugars are widely recognized for their ability to stabilize cell membranes during dehydration.However,the precise mechanisms by which sugars interact with lipid bilayers remain unclear.This mini-review synthesizes fou...Sugars are widely recognized for their ability to stabilize cell membranes during dehydration.However,the precise mechanisms by which sugars interact with lipid bilayers remain unclear.This mini-review synthesizes four key hypotheses explaining sugar-mediated protection of dehydrated bilayers:the Water Replacement Hypothesis(WRH),Hydration Force Hypothesis(HFH),Headgroup Bridging Hypothesis(HBH),and Vitrification Hypothesis(VH).We argue that these mechanisms are not mutually exclusive but instead operate synergistically under different cellular contexts.We propose that these hypotheses are not mutually exclusive but likely operate under different cellular contexts.Future studies should prioritize the development of biologically realistic membrane models-incorporating diverse lipids,proteins,and asymmetric leaflets-to elucidate the exact roles and mechanisms of sugars in membrane stabilization.Such advancements will enhance our understanding of anhydrobiosis and inform cryopreservation strategies for mammalian cells.展开更多
In two-dimensional bilayer systems,twist-angle-dependent electronic and thermoelectric properties have garnered significant scientific interest in recent years.In this work,based on a combination of density functional...In two-dimensional bilayer systems,twist-angle-dependent electronic and thermoelectric properties have garnered significant scientific interest in recent years.In this work,based on a combination of density functional theory and nonequilibrium Green’s function method,we explore the electronic and thermoelectric properties in blue-phosphorene nanoribbon-based heterojunction(BPNRHJ)with and without blue-phosphorene nanoribbon(BPNR)stack.Our calculations find that the electronic conductance and power factor can be strongly enhanced by the BPNR stack,and their enhancements can be further observed with the twist between the layers.The main reason for this is the electronic hybridization between the layers can provide new transport channels,and the twist can modulate the strength of interlayer electronic hybridization,resulting in extremely violent fluctuations in electron transmission and hence an enhanced power factor.While the phonon thermal conductance exhibits very low dependence on the layer stack and twist.Combining these factors,our results reveal that the thermoelectric performance can be greatly modulated and enhanced in twist bilayer BPNRHJ:the figure of merit will be over 2.5 in 4-4-ZBPNR@ZGNR-AA-8.8∘at 500 K.展开更多
Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution an...Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.展开更多
The semiconductor gas sensors used for xylene gas detection in real time has been restricted by the inadequate sensitivity and selectivity.Constructing a bilayer cascade sensor with the catalysis-gas sensitivity syner...The semiconductor gas sensors used for xylene gas detection in real time has been restricted by the inadequate sensitivity and selectivity.Constructing a bilayer cascade sensor with the catalysis-gas sensitivity synergistic is considered as an effective solution.Herein,the Ag@CeO_(2)nanosheets are synthesized by heat treating the Ag@Ce-MOF,which synthesized via solvothermal method.The morphological evolution of cerium metalorganic framework(Ce-MOF),regulated by Ag ions,is investigated,and the transformation mechanism is proposed.The bilayer sensors were constructed by using WO_(3)nanofibers,prepared via the electrospinning method,as the sensitive layer and the Ag@CeO_(2)nanosheets as the catalytic layer,respectively.The bilayer sensors exhibit remarkable performance in response to xylene.The response value(R_(a)/R_(g))of WO_(3)/Ag@CeO_(2)sensor to10 ppm xylene gas reaches 32.13 at the operating temperature of 160℃.Additionally,the sensor displays an exceptional response to even trace amounts of xylene,as low as parts per billion(ppb).The catalysis-gas sensitivity synergistic mechanism was elucidated by capturing catalytic intermediates using online mass spectrometry.These findings provide a novel strategy for benzene series(BTEX)sensor and offer a novel approach to prepare twodimensional Ce-MOF and its derived materials with tailored properties.展开更多
Recent discovery of high transition temperature superconductivity in La_(3)Ni_(2)O_(7) has sparked renewed theoretical and experimental interests in unconventional superconductivity. It is crucial to understand the in...Recent discovery of high transition temperature superconductivity in La_(3)Ni_(2)O_(7) has sparked renewed theoretical and experimental interests in unconventional superconductivity. It is crucial to understand the influence of various factors on its superconductivity. By refining the determinant quantum Monte Carlo algorithm, we characterize the parameter dependence of the superconducting transition temperature within a bilayer Hubbard model, which is sign-problem-free at arbitrary filling. A striking feature of this model is its similarity to the bilayer nickelate-based superconductor La_(3)Ni_(2)O_(7), where superconductivity emerges from the bilayer NiO_(2) planes.We find that interlayer spin-exchange J is critical to interlayer pairing, and that on-site interaction U contributes negatively to superconductivity at low doping levels but positively at high doping levels. Our findings can provide a reference for the next step in theoretical research on nickelate-based superconductors.展开更多
Applying a perpendicular electric field to bilayer graphene(BLG)induces an electrically tunable bandgap,so that insulating states with resistances exceeding~10^(8)Ωcan be generated.These high-resistance states pinch ...Applying a perpendicular electric field to bilayer graphene(BLG)induces an electrically tunable bandgap,so that insulating states with resistances exceeding~10^(8)Ωcan be generated.These high-resistance states pinch off the conducting channel,thereby enabling high-quality gated devices for classical and quantum electronics.However,it is challenging to precisely quantify these states electrically due to their high resistances,especially when different areas of the device are operated in different high-resistance states.Here,taking advantage of the strong acoustoelectric effect,we demonstrate the detection of these high-resistance states in a multi-gated BLG device using surface acoustic waves.Under different gating configurations,the device is operated in different high-resistance states.Although these states have similar resistances of~10^(8)Ω,we show their acoustoelectric responses exhibit pronounced differences,thereby allowing the acoustic detection.More interestingly,we demonstrate that when the conducting channel is pinched off by one top gate,we are still able to acoustically,but not electrically,detect the gating effect of another top gate.Our results reveal the powerful capability and the promising future of acoustically characterizing BLG and other two-dimensional materials,especially their electronic states with high resistances.展开更多
The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematica...The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematically investigate the influence of interlayer sliding on the electronic behavior of PtSe_(2) using density functional theory(DFT) calculations. Our results demonstrate that interlayer sliding induces a pronounced photocurrent spanning the short-wavelength infrared to visible spectral ranges. Remarkably, under an applied gate voltage, the sliding ferroelectric PtSe_(2) exhibits anomalously enhanced photovoltaic performance and an ultrahigh extinction ratio.Transmission spectral analysis reveals that this phenomenon originates from band structure modifications driven by energy-level transitions. Furthermore, the observed photocurrent enhancement via sliding ferroelectricity demonstrates universality across diverse platinum-based optoelectronic devices. This study introduces a novel paradigm for tailoring the intrinsic characteristics of 2D vdW semiconductors, expanding the design space for next-generation ferroelectric materials in advanced optoelectronic applications.展开更多
In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE inte...In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE interface involves the accumulation of opposite charges on both sides of the interface,thereby complicating the comprehension of the interfacial charging phenomenon.This study investigates the fundamental mechanisms of charge accumulation and the associated homo-junction effect in homo-bilayer XLPE(H-XLPE).Space charge analysis,model calculations based on Maxwell's equations,and thermal stimulation depolarisation current(TSDC)measurements were performed.Space charge results show that the homo-junctioninduced charge accumulation causes greater electric field distortion,leading to lower breakdown strength of H-XLPE compared to single-layer XLPE.Model calculations indicate that the density of opposite charges on the interface is attributed to the local gradient of reciprocal conductivity in the H-XLPE interface region.TSDC measurements on XLPE and H-XLPE enabled extraction of trap parameters and analysis of the charge transport process.The findings provide experimental evidence and theoretical clue for elucidating the role of the interface area on the charge accumulation that affects reliability and stability of submarine cable systems.展开更多
Two-dimensional(2D)moirésuperlattices have emerged as a versatile platform for uncovering exotic quantum phases,many of which arise in bilayer systems exhibiting Archimedean tessellation patterns such as triangul...Two-dimensional(2D)moirésuperlattices have emerged as a versatile platform for uncovering exotic quantum phases,many of which arise in bilayer systems exhibiting Archimedean tessellation patterns such as triangular,hexagonal,and kagome lattices.Here,we propose a strategy to engineer semiregular tessellation patterns in untwisted bilayer graphene by applying anisotropic epitaxial tensile strain(AETS)along crystallographic directions.Through force-field and firstprinciples calculations,we demonstrate that AETS can induce a rich variety of semiregular tessellation geometries,including truncated hextille,prismatic pentagon,and brick-phase arrangements.Characteristic electronic Dirac and flat bands of the lattice models associated with these semiregular tessellations are observed near the Fermi level,arising from interlayer interactions generated by the spatial rearrangement of AB,BA,and SP domains.Furthermore,the real-space observations of electronic kagome,distorted Lieb,brick-like,and one-dimensional stripe lattices demonstrate that AETS enables tunable semiregular tessellation lattices.Our study identifies AETS as a promising new degree of freedom in moiréengineering,offering a reproducible and scalable platform for exploring exotic electronic lattices in moirésystems.展开更多
Twist,the very degree of freedom in van der Waals heterostructures,offers a compelling avenue to manipulate and tailor their electrical and optical characteristics.In particular,moirépatterns in twisted homobilay...Twist,the very degree of freedom in van der Waals heterostructures,offers a compelling avenue to manipulate and tailor their electrical and optical characteristics.In particular,moirépatterns in twisted homobilayer transition metal dichalcogenides(TMDs)lead to zone folding and miniband formation in the resulting electronic bands,holding the promise to exhibit inter-layer excitonic optical phenomena.Although some experiments have shown the existence of twist-angle-dependent intra-and inter-layer excitons in twisted MoSe2 homobilayers,electrical control of the interlayer excitons in MoSe_(2) is relatively under-explored.Here,we show the signatures of the moiréeffect on intralayer and interlayer excitons in 2H-stacked twisted MoSe2 homobilayers.Doping-and electric field-dependent photoluminescence mea-surements at low temperatures give evidence of the momentum-direct K-K intralayer excitons,and the momentum-indirect Г-K and Г-Q interlayer excitons.Our results suggest that twisted MoSe_(2) homobilayers are an intriguing platform for engineering interlayer exciton states,which may shed light on future atomically thin optoelectronic applications.展开更多
We theoretically investigated the chiral phonons of honeycomb-type bilayer Wigner crystals recently discovered in van der Waals structures of layered transition metal dichalcogenides. These chiral phonons can emerge u...We theoretically investigated the chiral phonons of honeycomb-type bilayer Wigner crystals recently discovered in van der Waals structures of layered transition metal dichalcogenides. These chiral phonons can emerge under the inversion symmetry breaking introduced by an effective mass imbalance between the two layers or a moiré potential in one layer, as well as under the time-reversal symmetry breaking realized by applying a magnetic field. Considering the wide tunability of layered materials, the frequencies and chirality of phonons can both be tuned by varying the system parameters. These findings suggest that bilayer honeycomb-type Wigner crystals can serve as an exciting new platform for studying chiral phonons.展开更多
All-optical image processing has been viewed as a promising technique for its high computation speed and low power consumption.However,current methods are often restricted to few functionalities and low reconfigurabil...All-optical image processing has been viewed as a promising technique for its high computation speed and low power consumption.However,current methods are often restricted to few functionalities and low reconfigurabilities,which cannot meet the growing demand for device integration and scenario adaptation in next-generation vision regimes.Here,we propose and experimentally demonstrate a bilayer liquid crystal computing platform for reconfigurable image processing.Under different in-situ/ex-situ twisted/untwisted conditions of the layers,our approach allows for eight kinds of image processing functions,including one/two-channel bright field imaging,one/two-channel vortex filtering,horizontally/vertically one-dimensional edge detection,vertex detection,and photonic spin Hall effect-based resolution adjustable edge detection.A unified theoretical framework for this scheme is established on the transfer function theory,which coincides well with the experimental results.The proposed method offers an easily-switchable multi-functional solution to optical image processing by introducing mechanical degrees of freedom,which may enable emerging applications in computer vision,autonomous driving,and biomedical microscopy.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52225207 and 52350001)the Shanghai Pilot Program for Basic Research–Fudan University 21TQ1400100(Grant No.21TQ006)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)。
文摘When two layers of graphene are stacked with a twist angle of approximately 1.1°,strong interlayer coupling gives rise to a pair of flat bands in twisted bilayer graphene(TBG),resulting in pronounced electron–electron interactions.At half filling of the flat bands,TBG exhibits correlated insulating states.Here,we investigate the electrical transport properties of heterostructures composed of TBG and the antiferromagnetic insulator chromium oxychloride(CrOCl),and propose a strategy to modulate the correlated insulating states in TBG.During the transition from a conventional phase to a strong interfacial coupling phase,kink-like features are observed in the charge neutrality point(CNP),correlated insulating state,and band insulating state.Under a perpendicular magnetic field,the system exhibits broadened quantum Hall plateaus in the strong interfacial coupling regime.Electrons localized in the CrOCl layer screen the bottom gate,rendering the carrier density in TBG less sensitive to variations in the bottom gate voltage.These phenomena are well captured by a charge-transfer model between TBG and CrOCl.Our results provide insights into the control of electronic correlations and topological states in graphene moirésystems via interfacial charge coupling.
文摘In this study,we developed a novel bilayered scaffold consisting of a bottom layer composed of the Decellularized Bovine Pericardium(DP)coated with Polyaniline Nanoparticles(PANINPs)and a top layer made of an electrospun Poly(lactic-co-glycolic acid)/Gelatin(PLGA/Gel)membrane incorporated with Vascular Endothelial Growth Fac-tor(VEGF)and hawthorn extract.Functionally,the DP supplies native Extracellular Matrix(ECM)components and mechanical support,while PANINPs provide conductivity.The electrospun PLGA/Gel layer mimics fibrous ECM.It incorporates bioactives,with VEGF promoting pro-angiogenic stimulation and hawthorn extract enhanc-ing anticoagulant activity,as well as increasing surface hydrophilicity.The tissue adhesive ensures the interfacial integrity between the two layers.Decellularization efficiency was confirmed histologically using 4',6-diamidino-2-phenylindole(DAPI)and Hematoxylin-Eosin(H&E)staining.The DP exhibited a DNA content of 115.9±47.8 ng/mg DNA,compared to 982.88±395.42 ng/mg in Native Pericardium(NP).The PANINPs had an average par-ticle size of 104.94±13.7 nm.The conductivity of PANINPs-coated decellularized pericardium was measured to be 9.093±8.6×10-4 S/cm using the four-point probe method.PLGA/Gel membranes containing hawthorn extract(1%,5%,10%,and 15%w/v)and VEGF(0.1μg/mL,0.5μg/mL,and 1μg/mL)were fabricated by electrospinning,result-ing in fiber diameters between 850 and 1200 nm and pore sizes between 14 and 20μm.The anticoagulant efficiency of the membranes containing hawthorn extract reached 430 s in the Activated Partial Thromboplastin Time Assay(aPTT).Mechanical testing revealed a tensile strength of 22.70±6.33 MPa,an elongation of 53.58±10.63%,and Young's modulus of 0.67±0.10 MPa.The scaffold also exhibited over 91%cell viability and excellent cardiomyo-cyte adhesion.The hemolysis ratio was determined to be 0.421±0.191%,which confirms its blood compatibility.Our results indicate that the proposed bilayered scaffold can be a promising candidate for cardiac patch applications.
基金Project(4013311)supported by the National Science Foundation of Iran(INSF)。
文摘This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the prepared surfaces are placed on top of each other and by rolling with reduction more than 50%,the bonding between layers is established.In this research,the roll bonding process was done at room temperature,without the use of lubricants and with a 70%thickness reduction.Then,the final thickness of the Ag/Al bilayer sheet reached 350μm by several stages of cold rolling.Before cold rolling,it should be noted that to decrease the hardness created due to plastic deformation,the roll-bonded samples were subjected to annealing heat treatment at 400℃for 90 min.Thus,the final samples were annealed at 200,300 and 400℃for 90 min and cooled in a furnace to examine the annealing temperature effects.The uniaxial tensile and microhardness tests measured mechanical properties.Also,to investigate the fracture mechanism,the fractography of the cross-section was examined by scanning electron microscope(SEM).To evaluate the formability of Ag/Al bilayer sheets,forming limit curves were obtained experimentally through the Nakazima test.The resistance of composites to failure due to cracking was also investigated by fracture toughness.The results showed that annealing increases the elongation and formability of the Ag/Al bilayer sheet while reduces the ultimate tensile strength and fracture toughness.However,the changing trend is not the same at different temperatures,and according to the results,the most significant effect is obtained at 300℃and aluminum layers.It was also determined that by increasing annealing temperature,the fracture mechanism from shear ductile with small and shallow dimples becomes ductile with deep cavities.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1402802)the National Natural Science Foundation of China(Grant Nos.12494591 and 92165204)+4 种基金the Leading Talent Program of Guangdong Special Projects(Grant No.201626003)the Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008)the Research Center for Magnetoelectric Physics of Guangdong Province(Grant No.2024B0303390001)the Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2401010)supported by the National Natural Science Foundation of China(Grant Nos.12234016 and 12074031)。
文摘We investigate the energy bands,magnetism,and superconductivity of bilayer octagraphene with A-A stackingunder a perpendicular electric field.A tight-binding model is used to analyze the band structure of the system.The doubling of the unit cell results in each band of the single layer splitting into two.We find that applyinga perpendicular electric field increases the band splitting.As the electric field strength increases,the nestingof the Fermi surface(FS)weakens,eventually disrupting the antiferromagnetic order,and bilayer octagrapheneexhibits superconductivity.Spin fluctuations can induce unconventional superconductivity with s±-wave pairing.Applying a perpendicular electric field to bilayer octagraphene parent weakens the nesting of the FS,ultimatelykilling the spin-density-wave(SDW)ordered state and transitioning it into the superconducting state,whichworks as a doping effect.We use the random-phase approximation approach to obtain the pairing eigenvaluesand pairing symmetries of the perpendicular electric field-tuned bilayer octagraphene in the weak coupling limit.By tuning the strength of the perpendicular electric field,the critical interaction strength for SDW order can bemodified,which in turn may promote the emergence of unconventional superconductivity.
基金support from Generalitat Valenciana under Pla Complementari“Programa de Materials Avanc¸ats”,2022(grant number MFA/2022/030)Ministerio de Ciencia,Innovaci´on y Universidades(Spain)(grant number MCIN/AEI/10.13039/501100011033)+1 种基金support from UJI(UJI-2023-16 and GACUJIMC/2023/08)Generalitat Valenciana through FPI Fellowship Program(grant numbers ACIF/2020/294 and CIACIF/2021/050).
文摘This study demonstrates the successful fabrication of solid-state bilayers using LiFePO_(4)(LFP)cathodes and Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)-based Composite Solid Electrolytes(CSEs)via Cold Sintering Process(CSP).By optimizing the sintering pressure,it is achieved an intimate contact between the cathode and the solid electrolyte,leading to an enhanced electrochemical performance.Bilayers cold sintered at 300 MPa and a low-sintering temperature of 150℃exhibit high ionic conductivities(0.5 mS cm^(-1))and stable specific capacities at room temperature(160.1 mAh g^(-1)LFP at C/10 and 75.8 mAh g^(-1)_(LFP)at 1 C).Moreover,an operando electrochemical impedance spectroscopy(EIS)technique is employed to identify limiting factors of the bilayer kinetics and to anticipate the overall electrochemical behavior.Results suggest that capacity fading can occur in samples prepared with high sintering pressures due to a volume reduction in the LFP crystalline cell.This work demonstrates the potential of CSP to produce straightforward high-performance bilayers and introduces a valuable non-destructive instrument for understanding and avoiding degradation in solid-state lithium-based batteries.
基金the supports from Westlake Education Foundationthe support provided by the National Natural Science Foundation of China(Grant No.12304049)。
文摘We demonstrate that the sliding motion between two layers of the newly discovered ferroelectric and topologically trivial bismuth(Bi)monolayer[Nature 61767(2023)]can induce a sequence of topological phase transitions,alternating between Z_(2)trivial and nontrivial states.The lateral shift,while preserving spatial symmetry,can switch the quantum spin Hall state on and of.The sliding-induced changes in out-of-plane atomic buckling,which are directly coupled to in-plane ferroelectricity,are shown to signifcantly modulate the band gap and drive the topological phase transitions.We map out the topological phase diagram and in-plane ferroelectricity with respect to sliding displacements.With appropriate sliding,the bismuth bilayer can transition into a nontrivial polar metal,exhibiting a pronounced shift current response arising from interband geometric quantities of electronic bands.Moreover,bilayer Bi supports a sliding-tunable nonlinear anomalous Hall response resulting from the geometric Berry curvature dipole.Confgurations that are Z_(2)nontrivial can generate drastically different transverse currents orthogonal to the external electric feld,as both the direction and magnitude of the Berry curvature dipole at the Fermi level are highly sensitive to the sliding displacement.Our results suggest that bilayer bismuth,with its ability to generate multiple types of geometric currents,ofers a versatile platform for power-efcient“Berry slidetronics”for multistate memory applications integrating both band topology and ferroelectricity.
基金supported by grants from the China Postdoctoral Science Foundation(Nos.2022TQ0397,2022MD723744,2022M710564,2022M720603)Natural Science Foundation of China(Nos.82272553,82102571,81974346,8210257,82472404)+8 种基金Chongqing Municipal Medical Youth Talent Support Program,Chongqing,China(No.YXQN202408)Natural Science Foundation of Chongqing,China(Nos.CSTB2022NSCQ-MSX0089,CSTB2022NSCQ-MSX0104,CSTB2024NSCQMSX0532)Joint Medical Research Project of Health Commission&Science and Technology Bureau of Chongqing,China(No.2024QNXM032)Special Project for the Central Government to Guide the Development of Local Science and Technology in Sichuan Province(No.2023ZYD0071)National Natural Science Foundation of Sichuan(No.24NSFSC1274)Project of Innovative Science Research for Postgraduate of Chongqing Municipal Education Committee,Chongqing,China(Nos.CYS22389,CYB240224)National Natural Science Foundation of Sichuan(No.2024NSFSC0678)Research Project of the Affiliated Hospital of North Sichuan Medical College(Nos.2023ZD002,2023-2ZD001,2024JB001)Disciplines Construction Program of The Third Affiliated Hospital of Chongqing Medical University(Nos.KY23035,KY23041).
文摘Osteochondral defects pose an enormous challenge,and no satisfactory therapy is available to date due to the hierarchy of the native tissue consisting of articular cartilage and subchondral bone.Constructing a scaffold with biological function and biomimetic structure is the key to achieving a high-quality repair effect.Herein,a natural polymer-based bilayer scaffold with a porous architecture similar to that of osteochondral tissue is designed,involving the transforming growth factor-beta3-liposome-loaded upper layer for superficial cartilage regeneration and the nanohydroxyapatite-coated lower layer for subchondral bone rehabilitation.This research is conducted to evaluate the effects of nanoparticle-modified bilayer scaffold to mimic the hierarchical pro-chondrogenic and proosteogenic microenvironment for the recruited endogenous bone marrow mesenchymal stem cells.The fabricated composites were evaluated for mechanical,physicochemical,biological properties,in vitro and in vivo tissue regeneration potential.Overall,the current bilayer scaffold could regenerate a cartilage-bone integrated tissue with a seamless interfacial integration and exhibited superior tissue repair outcomes compared to other single layer scaffolds based on morphological,radiological and histological evaluation,verifying that this novel graft could be an effective approach to tissue-engineered analogs of cartilage-subchondral bone and offer new therapeutic opportunities for osteochondral defect-associated diseases.
基金supported by the Natural Science Foundation of Guangdong Province of China(Grant No.2025A1515011071)the National Natural Science Foundation of China(Grant Nos.92065110,11974048,and 12074334)the Beijing Municipal Natural Science Foundation Key Research Topics(Grant No.Z230006)。
文摘Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.
基金supported by the National Natural Science Foundation of China,China(Grant No.52376052)the Anhui Provincial Natural Science Foundation,China(Grant No.2308085ME174).
文摘Sugars are widely recognized for their ability to stabilize cell membranes during dehydration.However,the precise mechanisms by which sugars interact with lipid bilayers remain unclear.This mini-review synthesizes four key hypotheses explaining sugar-mediated protection of dehydrated bilayers:the Water Replacement Hypothesis(WRH),Hydration Force Hypothesis(HFH),Headgroup Bridging Hypothesis(HBH),and Vitrification Hypothesis(VH).We argue that these mechanisms are not mutually exclusive but instead operate synergistically under different cellular contexts.We propose that these hypotheses are not mutually exclusive but likely operate under different cellular contexts.Future studies should prioritize the development of biologically realistic membrane models-incorporating diverse lipids,proteins,and asymmetric leaflets-to elucidate the exact roles and mechanisms of sugars in membrane stabilization.Such advancements will enhance our understanding of anhydrobiosis and inform cryopreservation strategies for mammalian cells.
基金supported by the Key Projects of Department of Education of Hunan Province,China(Grant No.21A0167)the Natural Science Foundation of Hunan Province,China(Grant No.2019JJ40532)the Talent Introducing Foundation of Central South University of Forestry and Technology(Grant No.104-0160)。
文摘In two-dimensional bilayer systems,twist-angle-dependent electronic and thermoelectric properties have garnered significant scientific interest in recent years.In this work,based on a combination of density functional theory and nonequilibrium Green’s function method,we explore the electronic and thermoelectric properties in blue-phosphorene nanoribbon-based heterojunction(BPNRHJ)with and without blue-phosphorene nanoribbon(BPNR)stack.Our calculations find that the electronic conductance and power factor can be strongly enhanced by the BPNR stack,and their enhancements can be further observed with the twist between the layers.The main reason for this is the electronic hybridization between the layers can provide new transport channels,and the twist can modulate the strength of interlayer electronic hybridization,resulting in extremely violent fluctuations in electron transmission and hence an enhanced power factor.While the phonon thermal conductance exhibits very low dependence on the layer stack and twist.Combining these factors,our results reveal that the thermoelectric performance can be greatly modulated and enhanced in twist bilayer BPNRHJ:the figure of merit will be over 2.5 in 4-4-ZBPNR@ZGNR-AA-8.8∘at 500 K.
基金the National Natural Science Foundation of China(52090034,52273064,52221006)the Fundamental Research Funds for the Central Universities(JD2417)is gratefully acknowledged.
文摘Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.
基金financially supported by the National Natural Science Foundation of China(Nos.62471303,62071300,22176127,22301181,22406130 and 22476131)Shanghai Sailing Program(Nos.23YF1429000 and 22YF1430400)
文摘The semiconductor gas sensors used for xylene gas detection in real time has been restricted by the inadequate sensitivity and selectivity.Constructing a bilayer cascade sensor with the catalysis-gas sensitivity synergistic is considered as an effective solution.Herein,the Ag@CeO_(2)nanosheets are synthesized by heat treating the Ag@Ce-MOF,which synthesized via solvothermal method.The morphological evolution of cerium metalorganic framework(Ce-MOF),regulated by Ag ions,is investigated,and the transformation mechanism is proposed.The bilayer sensors were constructed by using WO_(3)nanofibers,prepared via the electrospinning method,as the sensitive layer and the Ag@CeO_(2)nanosheets as the catalytic layer,respectively.The bilayer sensors exhibit remarkable performance in response to xylene.The response value(R_(a)/R_(g))of WO_(3)/Ag@CeO_(2)sensor to10 ppm xylene gas reaches 32.13 at the operating temperature of 160℃.Additionally,the sensor displays an exceptional response to even trace amounts of xylene,as low as parts per billion(ppb).The catalysis-gas sensitivity synergistic mechanism was elucidated by capturing catalytic intermediates using online mass spectrometry.These findings provide a novel strategy for benzene series(BTEX)sensor and offer a novel approach to prepare twodimensional Ce-MOF and its derived materials with tailored properties.
基金supported by the National Natural Science Foundation of China (Grant Nos.12234016,12174317 for C.Wu,and 12474218 for R.Ma,Z.Fan,and T.Ma)Beijing Natural Science Foundation (Grant No.1242022 for R.Ma,Z.Fan,and T.Ma)the New Cornerstone Science Foundation。
文摘Recent discovery of high transition temperature superconductivity in La_(3)Ni_(2)O_(7) has sparked renewed theoretical and experimental interests in unconventional superconductivity. It is crucial to understand the influence of various factors on its superconductivity. By refining the determinant quantum Monte Carlo algorithm, we characterize the parameter dependence of the superconducting transition temperature within a bilayer Hubbard model, which is sign-problem-free at arbitrary filling. A striking feature of this model is its similarity to the bilayer nickelate-based superconductor La_(3)Ni_(2)O_(7), where superconductivity emerges from the bilayer NiO_(2) planes.We find that interlayer spin-exchange J is critical to interlayer pairing, and that on-site interaction U contributes negatively to superconductivity at low doping levels but positively at high doping levels. Our findings can provide a reference for the next step in theoretical research on nickelate-based superconductors.
基金Project supported by the Natural Science Foundation of Jiangsu Province(Grant No.BK20240123)the National Key Research and Development Program of China(Grant No.2022YFA1405900)the National Natural Science Foundation of China(Grant Nos.12274397,12274401,and 12034018)。
文摘Applying a perpendicular electric field to bilayer graphene(BLG)induces an electrically tunable bandgap,so that insulating states with resistances exceeding~10^(8)Ωcan be generated.These high-resistance states pinch off the conducting channel,thereby enabling high-quality gated devices for classical and quantum electronics.However,it is challenging to precisely quantify these states electrically due to their high resistances,especially when different areas of the device are operated in different high-resistance states.Here,taking advantage of the strong acoustoelectric effect,we demonstrate the detection of these high-resistance states in a multi-gated BLG device using surface acoustic waves.Under different gating configurations,the device is operated in different high-resistance states.Although these states have similar resistances of~10^(8)Ω,we show their acoustoelectric responses exhibit pronounced differences,thereby allowing the acoustic detection.More interestingly,we demonstrate that when the conducting channel is pinched off by one top gate,we are still able to acoustically,but not electrically,detect the gating effect of another top gate.Our results reveal the powerful capability and the promising future of acoustically characterizing BLG and other two-dimensional materials,especially their electronic states with high resistances.
基金supported by the National Key Research and Development Program of China (Grant No. 2024YFB3211701)the National Natural Science Foundation of China (Grant Nos. T2222011, 62174026, and 12274234)+1 种基金the National Key Research and Development Program of China (Grant Nos. 2023YFB3611400 and 2019YFA0308000)the Fundamental Research Funds for the Central Universities (Grant No. 242023k30027)。
文摘The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematically investigate the influence of interlayer sliding on the electronic behavior of PtSe_(2) using density functional theory(DFT) calculations. Our results demonstrate that interlayer sliding induces a pronounced photocurrent spanning the short-wavelength infrared to visible spectral ranges. Remarkably, under an applied gate voltage, the sliding ferroelectric PtSe_(2) exhibits anomalously enhanced photovoltaic performance and an ultrahigh extinction ratio.Transmission spectral analysis reveals that this phenomenon originates from band structure modifications driven by energy-level transitions. Furthermore, the observed photocurrent enhancement via sliding ferroelectricity demonstrates universality across diverse platinum-based optoelectronic devices. This study introduces a novel paradigm for tailoring the intrinsic characteristics of 2D vdW semiconductors, expanding the design space for next-generation ferroelectric materials in advanced optoelectronic applications.
基金supported by Program of Beijing Huairou Laboratory(Grant ZD2022003A).
文摘In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE interface involves the accumulation of opposite charges on both sides of the interface,thereby complicating the comprehension of the interfacial charging phenomenon.This study investigates the fundamental mechanisms of charge accumulation and the associated homo-junction effect in homo-bilayer XLPE(H-XLPE).Space charge analysis,model calculations based on Maxwell's equations,and thermal stimulation depolarisation current(TSDC)measurements were performed.Space charge results show that the homo-junctioninduced charge accumulation causes greater electric field distortion,leading to lower breakdown strength of H-XLPE compared to single-layer XLPE.Model calculations indicate that the density of opposite charges on the interface is attributed to the local gradient of reciprocal conductivity in the H-XLPE interface region.TSDC measurements on XLPE and H-XLPE enabled extraction of trap parameters and analysis of the charge transport process.The findings provide experimental evidence and theoretical clue for elucidating the role of the interface area on the charge accumulation that affects reliability and stability of submarine cable systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.52461160327,92477205,12474173,and 12104313)the National Key R&D Program of China(Grant No.2023YFA1406500)+3 种基金the Department of Science and Technology of Guangdong Province(Grant No.2021QN02L820)Shenzhen Science and Technology Program(Grant No.RCYX20231211090126026,the Stable Support Plan Program 20220810161616001)the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(Grant No.22XNKJ30)。
文摘Two-dimensional(2D)moirésuperlattices have emerged as a versatile platform for uncovering exotic quantum phases,many of which arise in bilayer systems exhibiting Archimedean tessellation patterns such as triangular,hexagonal,and kagome lattices.Here,we propose a strategy to engineer semiregular tessellation patterns in untwisted bilayer graphene by applying anisotropic epitaxial tensile strain(AETS)along crystallographic directions.Through force-field and firstprinciples calculations,we demonstrate that AETS can induce a rich variety of semiregular tessellation geometries,including truncated hextille,prismatic pentagon,and brick-phase arrangements.Characteristic electronic Dirac and flat bands of the lattice models associated with these semiregular tessellations are observed near the Fermi level,arising from interlayer interactions generated by the spatial rearrangement of AB,BA,and SP domains.Furthermore,the real-space observations of electronic kagome,distorted Lieb,brick-like,and one-dimensional stripe lattices demonstrate that AETS enables tunable semiregular tessellation lattices.Our study identifies AETS as a promising new degree of freedom in moiréengineering,offering a reproducible and scalable platform for exploring exotic electronic lattices in moirésystems.
基金supported by the National Key R&D Program of China(No.2023YFF1500600)the National Natural Science Foun-dation of China(Nos.12004259,12204287)+3 种基金China Postdoc-toral Science Foundation(Grant No.2022M723215)Zheng Vitto Han acknowledges the support of the Fund for Shanxi“1331 Project”Key Subjects Construction,and the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302003)Kenji Watanabe and Takashi Taniguchi acknowledge support from the JSPS KAKENHI(Grant Nos.20H00354 and 23H02052)the World Premier International Research Center Initiative(WPI),MEXT,Japan.
文摘Twist,the very degree of freedom in van der Waals heterostructures,offers a compelling avenue to manipulate and tailor their electrical and optical characteristics.In particular,moirépatterns in twisted homobilayer transition metal dichalcogenides(TMDs)lead to zone folding and miniband formation in the resulting electronic bands,holding the promise to exhibit inter-layer excitonic optical phenomena.Although some experiments have shown the existence of twist-angle-dependent intra-and inter-layer excitons in twisted MoSe2 homobilayers,electrical control of the interlayer excitons in MoSe_(2) is relatively under-explored.Here,we show the signatures of the moiréeffect on intralayer and interlayer excitons in 2H-stacked twisted MoSe2 homobilayers.Doping-and electric field-dependent photoluminescence mea-surements at low temperatures give evidence of the momentum-direct K-K intralayer excitons,and the momentum-indirect Г-K and Г-Q interlayer excitons.Our results suggest that twisted MoSe_(2) homobilayers are an intriguing platform for engineering interlayer exciton states,which may shed light on future atomically thin optoelectronic applications.
基金supported by Tencent’s Program of Aspiring Explorers in Sciencesupport by the National Natural Science Foundation of China (Grant No. 12274477)the Department of Science and Technology of Guangdong Province in China (Grant No. 2019QN01X061)。
文摘We theoretically investigated the chiral phonons of honeycomb-type bilayer Wigner crystals recently discovered in van der Waals structures of layered transition metal dichalcogenides. These chiral phonons can emerge under the inversion symmetry breaking introduced by an effective mass imbalance between the two layers or a moiré potential in one layer, as well as under the time-reversal symmetry breaking realized by applying a magnetic field. Considering the wide tunability of layered materials, the frequencies and chirality of phonons can both be tuned by varying the system parameters. These findings suggest that bilayer honeycomb-type Wigner crystals can serve as an exciting new platform for studying chiral phonons.
基金supported in part by the National Natural Science Foundation of China(12421005,12374273,and 61805077)in part by the Natural Science Foundation of Hunan Province(2025JJ50046)in part by the Hunan Provincial Major Sci-Tech Program(2023ZJ1010)。
文摘All-optical image processing has been viewed as a promising technique for its high computation speed and low power consumption.However,current methods are often restricted to few functionalities and low reconfigurabilities,which cannot meet the growing demand for device integration and scenario adaptation in next-generation vision regimes.Here,we propose and experimentally demonstrate a bilayer liquid crystal computing platform for reconfigurable image processing.Under different in-situ/ex-situ twisted/untwisted conditions of the layers,our approach allows for eight kinds of image processing functions,including one/two-channel bright field imaging,one/two-channel vortex filtering,horizontally/vertically one-dimensional edge detection,vertex detection,and photonic spin Hall effect-based resolution adjustable edge detection.A unified theoretical framework for this scheme is established on the transfer function theory,which coincides well with the experimental results.The proposed method offers an easily-switchable multi-functional solution to optical image processing by introducing mechanical degrees of freedom,which may enable emerging applications in computer vision,autonomous driving,and biomedical microscopy.
