Ru-based nanomaterials have been demonstrated to be highly active electrocatalysts for hydrogen evo-lution reaction(HER),yet weak water adsorption and splitting ability in neutral media thus it is rather difficult for...Ru-based nanomaterials have been demonstrated to be highly active electrocatalysts for hydrogen evo-lution reaction(HER),yet weak water adsorption and splitting ability in neutral media thus it is rather difficult for the intermediates to adsorb on the active site.Herein,we introduce a concept of the prox-imity effect,com prising adjacent Ru and RuO_(2) nanoparticles coupled on TiO_(2)(Ru/RuO_(2)-TiO_(2)),for the synergic promotion of water molecule adsorption and splitting,significantly enhancing HER electrocatal-ysis performance.The in-situ spectroscopy experiments and density function theory(DFT)simulations demonstrated that the proximity effect between the adjacent Ru nanoparticles and RuO_(2) nanoparticles can accelerate water adsorption and splitting.As a result,the as-made Ru/RuO_(2)-TiO_(2) only need overpo-tentials of 52.7,16.0,and 16.4 mV to achieve the current density of 10 mA cm-2 in neutral,acid,and alkaline media,respectively.The mass activity of Ru/RuO_(2)-TiO_(2) in neutral media is 320 and 117 times higher than that of commercial Ru/C and Pt/C at the overpotential of 100 mV,respectively.This work emphasizes the proximity effect for activation of reactants which can be extended to other electrocat-alytic reactions.展开更多
Two-dimensional(2D)magnet/superconductor heterostructures can promote the design of artificial materials for exploring 2D physics and device applications by exotic proximity effects.However,plagued by the low Curie te...Two-dimensional(2D)magnet/superconductor heterostructures can promote the design of artificial materials for exploring 2D physics and device applications by exotic proximity effects.However,plagued by the low Curie temperature and instability in air,it is hard to realize practical applications for the reported layered magnetic materials at present.In this paper,we developed a space-confined chemical vapor deposition method to synthesize ultrathin air-stable ε-Fe_(2)O_(3) nanosheets with Curie temperature above 350 K.The ε-Fe_(2)O_(3)/NbSe_(2) heterojunction was constructed to study the magnetic proximity effect on the superconductivity of the NbSe_(2) multilayer.The electrical transport results show that the subtle proximity effect can modulate the interfacial spin–orbit interaction while undegrading the superconducting critical parameters.Our work paves the way to construct 2D heterojunctions with ultrathin nonlayered materials and layered van der Waals(vdW)materials for exploring new physical phenomena.展开更多
A new method for determining proximity parameters α,β ,and η in electron beam lithography is introduced on the assumption that the point exposure spread function is composed of two Gaussians.A single line i...A new method for determining proximity parameters α,β ,and η in electron beam lithography is introduced on the assumption that the point exposure spread function is composed of two Gaussians.A single line is used as test pattern to determine proximity effect parameters and the normalization approach is adopted in experimental data transaction in order to eliminate the need of measuring exposure clearing dose of the resist.Furthermore,the parameters acquired by this method are successfully used for proximity effect correction in electron beam lithography on the same experimental conditions.展开更多
We present a detailed routing algorithm considering the optical proximity effect. The light intensity is calculated beforehand and stored in look-up tables. These costs are used as a constraint to guide the sequential...We present a detailed routing algorithm considering the optical proximity effect. The light intensity is calculated beforehand and stored in look-up tables. These costs are used as a constraint to guide the sequential routing. The routing algorithm is based on constructed force directed Steiner tree routing to enhance routing efficien- cy. Experimental results on industrial benchmark circuits show that the presented routing algorithm can obtain much improvement considering optical effects short runtime.展开更多
We describe the fabrication of metal nanogaps of sub-20nm in feature size using the proximity effect in electron beam lithography （EBL）. The proximity effect is extended to develop a flexible and practical method fo...We describe the fabrication of metal nanogaps of sub-20nm in feature size using the proximity effect in electron beam lithography （EBL）. The proximity effect is extended to develop a flexible and practical method for preparing metal （e. g. Au or Ag） nanogaps and arrays in combination with a transfer process （e. g., deposition/lift-off）. Different from the direct gap-writing process,the nanogap precursor structures （nanoconnections） were designed by GDSII software and then written by electron beam. Following a deposition and lift-off process, the metal nanogaps were obtained and the nanogap size can be lowered to -10nm by controlling the exposure dose in EBL.展开更多
The interaction between a promoter and an active metal crucially impacts catalytic performance.Nowadays,the influence of promoter contents and species has been intensively considered.In this study,we investigate the e...The interaction between a promoter and an active metal crucially impacts catalytic performance.Nowadays,the influence of promoter contents and species has been intensively considered.In this study,we investigate the effect of the iron(Fe)-zinc(Zn)proximity of Fe-Zn bimetallic catalysts on CO_(2)hydrogenation performance.To eliminate the size effect,Fe_(2)O_(3)and ZnO nanoparticles with uniform size are first prepared by the thermal decomposition method.By changing the loading sequence or mixing method,a series of Fe-Zn bimetallic catalysts with different Fe-Zn distances are obtained.Combined with a series of characterization techniques and catalytic performances,Fe-Zn bimetallic proximity for compositions of Fe species is discussed.Furthermore,we observe that a smaller Fe-Zn distance inhibits the reduction and carburization of the Fe species and facilitates the oxidation of carbides.Appropriate proximity of Fe and Zn(i.e.,Fe_1Zn_(1)-imp and Fe_(1)Zn_(1)-mix samples)results in a suitable ratio of the Fe_5C_(2)and Fe_(3)O_(4)phases,simultaneously promoting the reverse water-gas shift and Fischer-Tropsch synthesis reactions.This study provides insight into the proximity effect of bimetallic catalysts on CO_(2)hydrogenation performance.展开更多
Two-dimensional(2D)magnetic materials have aroused tremendous interest due to the 2D confinement of magnetism and potential applications in spintronic and valleytronic devices.However,most of the currently 2D magnetic...Two-dimensional(2D)magnetic materials have aroused tremendous interest due to the 2D confinement of magnetism and potential applications in spintronic and valleytronic devices.However,most of the currently 2D magnetic materials are achieved by the exfoliation from their bulks,of which the thickness and domain size are difficult to control,limiting the practical device applications.Here,we demonstrate the realization of thickness-tunable rhombohedral Cr_(2)Se_(3)nanosheets on different substrates via the chemical vapor deposition route.The magnetic transition temperature at about 75 K is observed.Furthermore,van der Waals heterostructures consisting of Cr_(2)Se_(3)nanosheets and monolayer WS2 are constructed.We observe the magnetic proximity effect in the heterostructures,which manifests the manipulation of the valley polarization in monolayer WS2.Our work contributes to the vapor growth and applications of 2D magnetic materials.展开更多
Topological insulators （Tls） are bulk insulators that possess robust helical conducting states along their interfaces with conventional insulators. A tremendous research effort has recently been devoted to TI-based ...Topological insulators （Tls） are bulk insulators that possess robust helical conducting states along their interfaces with conventional insulators. A tremendous research effort has recently been devoted to TI-based heterostructures, in which con- ventional proximity effects give rise to a series of exotic physical phenomena. This paper reviews our recent studies on the potential existence of topological proximity effects at the interface between a topological insulator and a normal insu- lator or other topologically trivial systems. Using first-principles approaches, we have realized the tunability of the vertical location of the topological helical state via intriguing dual-proximity effects. To further elucidate the control parameters of this effect, we have used the graphene-based heterostructures as prototypical systems to reveal a more complete phase diagram. On the application side of the topological helical states, we have presented a catalysis example, where the topo- logical helical state plays an essential role in facilitating surface reactions by serving as an effective electron bath, These discoveries lay the foundation for accurate manipulation of the real space properties of the topological helical state in TI- based heterostructures and pave the way for realization of the salient functionality of topological insulators in future device applications.展开更多
Recently, two-dimensional van der Waals(vd W) magnetic heterostructures have attracted intensive attention since they can show remarkable properties due to the magnetic proximity effect. In this work, the spin-polariz...Recently, two-dimensional van der Waals(vd W) magnetic heterostructures have attracted intensive attention since they can show remarkable properties due to the magnetic proximity effect. In this work, the spin-polarized electronic structures of antimonene/Fe_(3)GeTe_(2)vdW heterostructures were investigated through the first-principles calculations. Owing to the magnetic proximity effect, the spin splitting appears at the conduction-band minimum(CBM) and the valence-band maximum(VBM) of the antimonene. A low-energy effective Hamiltonian was proposed to depict the spin splitting. It was found that the spin splitting can be modulated by means of applying an external electric field, changing interlayer distance or changing stacking configuration. The spin splitting energy at the CBM monotonously increases as the external electric field changes from-5 V/nm to 5 V/nm, while the spin splitting energy at the VBM almost remains the same. Meanwhile,as the interlayer distance increases, the spin splitting energies at the CBM and VBM both decrease. The different stacking configurations can also induce different spin splitting energies at the CBM and VBM. Our work demonstrates that the spin splitting of antimonene in this heterostructure is not singly dependent on the nearest Sb–Fe distance, which indicates that magnetic proximity effect in heterostructures may be modulated by multiple factors, such as hybridization of electronic states and the local electronic environment. The results enrich the fundamental understanding of the magnetic proximity effect in two-dimensional vdW heterostructures.展开更多
We extend the Blonder, Tinkham and Klapwijk （BTK） theory to the study of the coexistence between ferromagnetism and s-wave superconductivity in ferromagnet/superconductor （F/S） structures. It is found that the fer...We extend the Blonder, Tinkham and Klapwijk （BTK） theory to the study of the coexistence between ferromagnetism and s-wave superconductivity in ferromagnet/superconductor （F/S） structures. It is found that the ferromagnetism and s-wave superconductivity can coexist near the F/S interface, which is induced by proximity effects. On the F side, the density of states （DOS） exhibits some superconducting-like properties, and it displays a damped oscillation from ‘0＇ to ‘v＇ states with increasing either the thickness of F film or the exchange energy. We also study the influences of the spin-polarized exchange splitting in the F and the spin-degeneracy by Rashba spin-orbit coupling （RSOC） in the two-dimensional electron gas （2DGE） on the proximity effects. It is shown that the case of Rashba spin-degeneracy is very different from that of the spin-polarized exchange splitting.展开更多
We report an experimental study of electron transport properties of MnSe/(Bi,Sb)_(2)Te_(3) heterostructures,in which MnSe is an antiferromagnetic insulator,and(Bi,Sb)_(2)Te_(3) is a three-dimensional topological insul...We report an experimental study of electron transport properties of MnSe/(Bi,Sb)_(2)Te_(3) heterostructures,in which MnSe is an antiferromagnetic insulator,and(Bi,Sb)_(2)Te_(3) is a three-dimensional topological insulator(TI).Strong magnetic proximity effect is manifested in the measurements of the Hall effect and longitudinal resistances.Our analysis shows that the gate voltage can substantially modify the anomalous Hall conductance,which exceeds 0.1 e^(2)/h at temperature T=1.6 K and magnetic field _(μ0)H=5 T,even though only the top TI surface is in proximity to MnSe.This work suggests that heterostructures based on antiferromagnetic insulators provide a promising platform for investigating a wide range of topological spintronic phenomena.展开更多
We analyse the proximity effect in hybrid nanoscale junctions involving superconducting leads. We develop a general framework for the analysis of the proximity effect using the same theoretical methods typically emplo...We analyse the proximity effect in hybrid nanoscale junctions involving superconducting leads. We develop a general framework for the analysis of the proximity effect using the same theoretical methods typically employed for the analysis of conductance properties. We apply our method to a normal-superconductor tunnel contact and compare our results to previous results.展开更多
Proximity-induced magnetic exchange interactions offer a novel approach to manipulate the valley degree of freedom(DOF)in nonmagnetic monolayers without external magnetic fields.Transition metal dichalcogenides(TMDs)s...Proximity-induced magnetic exchange interactions offer a novel approach to manipulate the valley degree of freedom(DOF)in nonmagnetic monolayers without external magnetic fields.Transition metal dichalcogenides(TMDs)serve as an ideal platform for valleytronics research.Here,by introducing a twodimensional(2D)magnetic substrate,chromium germanium telluride(CrGeTe_(3)),we demonstrate effective control over the spin and valley properties of CrGeTe_(3)/MTe_(2)(M=Mo,W)van der Waals(vdW)heterostructures.Our first-principles calculations and k·p model Hamiltonian analysis reveal that the magnetic proximity effect(MPE)induces valley splitting and polarization in monolayer MoTe_(2)and WTe_(2)through the synergistic action of spin-orbit coupling(SOC)and proximity exchange interactions.Further investigation shows that valley splitting in these heterostructures is highly sensitive to the overlap between the atomic projection positions of TMDs and the magnetic Cr atoms,and can be continuously adjusted by varying the magnetization of CrGeTe_(3).Additionally,normal strain and experimentally accessible electric fields can effectively modulate the proximity exchange coupling,thus enabling extensive tunability of valley splitting.These controllable manipulations of the valley DOF through external stimuli mark a significant advancement in valleytronics,paving the way for next-generation electronic devices with enhanced performance and novel functionalities.展开更多
Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon d...Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon dioxide emissions.However,high hydrogenation energy barrier for*NO intermediates and insufficient supply of active hydrogen cause slow hydrogenation process,and further result in low efficiency of nitrate conversion and ammonia synthesis.Herein,a series of tandem catalysts,one-dimensional coordination polymers(1D CCPs)with dual sites are synthesized and obtained 190.4 mg h^(-1)mgcat^(-1)ammonia production rate with Faradaic efficiency of 97.16%,outperforming to the most of recent reported catalysts.The catalytic performances are well-maintained even after a long-term stability test of 1200 h,laying the foundation for practical applications.Density functional theory results reveal that the stationary adsorbed*NO on Ni site induced proximity electronic effect could reduce the energy barrier for hydrogenation of*NO intermediates over Cu site.In addition,the Ni site in the dual sites 1D CCPs is conducive to generating active hydrogen,providing rich proton source to boost the hydrogenation of*NO,and further enhancing the compatibility of deoxygenation and hydrogenation process.Our work paves a new insight into the mechanism of NITRR process and will inspire more research interests in exploring the proximity electronic effect in catalytic process.展开更多
Recent studies have shown that the construction of nanophononic metamaterials can reduce thermal conductivity without affecting electrical properties,making them promising in many fields of application,such as energy ...Recent studies have shown that the construction of nanophononic metamaterials can reduce thermal conductivity without affecting electrical properties,making them promising in many fields of application,such as energy conversion and thermal management.However,although extensive studies have been carried out on thermal conductivity reduction in nanophononic metamaterials,the local heat flux characteristic is still unclear.In this work,we construct a heat flux regulator which includes a silicon nanofilm with silicon pillars.The regulator has remarkable heat flux regulation ability,and various impacts on the regulation ability are explored.Surprisingly,even in the region without nanopillars,the local heat current is still lower than that in pristine silicon nanofilms,reduced by the neighboring nanopillars through the thermal proximity effect.We combine the analysis of the phonon participation ratio with the intensity of localized phonon modes to provide a clear explanation.Our findings not only provide insights into the mechanisms of heat flux regulation by nanophononic metamaterials,but also will open up new research directions to control local heat flux for a broad range of applications,including heat management,thermoelectric energy conversion,thermal cloak,and thermal concentrator.展开更多
Spin-orbit interaction(SOI)can be introduced by the proximity effect to modulate the electronic properties of graphene-based heterostructures.In this work,we stack trilayer WSe_(2) on Bernal tetralayer graphene to inv...Spin-orbit interaction(SOI)can be introduced by the proximity effect to modulate the electronic properties of graphene-based heterostructures.In this work,we stack trilayer WSe_(2) on Bernal tetralayer graphene to investigate the influence of SOI on the anomalous Hall effect(AHE).In this structurally asymmetric device,by comparing the magnitude of AHE at positive and negative displacement fields,we find that AHE is strongly enhanced by bringing electrons in proximity to the WSe_(2) layer.Meanwhile,the enhanced AHE signal persists up to 80 K,providing important routes for topological device applications at high temperatures.展开更多
A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography.The sizes of exposed patterns depend on dose factors while other exposure parameters（including acceler...A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography.The sizes of exposed patterns depend on dose factors while other exposure parameters（including accelerate voltage,resist thickness,exposing step size,substrate material,and so on） remain constant.This method is based on two reasonable assumptions in the evaluation of the compensated dose factor：one is that the relation between dose factors and circle-diameters is linear in the range under consideration;the other is that the compensated dose factor is only affected by the nearest neighbors for simplicity.Four-layer-hexagon photonic crystal structures were fabricated as test patterns to demonstrate this method.Compared to the uncorrected structures,the homogeneity of the corrected hole-size in photonic crystal structures was clearly improved.展开更多
Here,we present a novel bioorthogonal platform that enables precise positioning of attached moieties in close proximity,thereby facilitating the discovery and optimization of biocompatible reactions.Using this platfor...Here,we present a novel bioorthogonal platform that enables precise positioning of attached moieties in close proximity,thereby facilitating the discovery and optimization of biocompatible reactions.Using this platform,we achieve a Horner-Wadsworth-Emmons(HWE)reaction under physiological conditions,generating a fluorophore in situ with a yield of up to 93%.This proximity platform should facilitate the discovery of various types of biocompatible reactions,making it a versatile tool for biomedical applica-tions.展开更多
The tunneling conductance of two kinds of tunnel junctions with time-reversal symmetry breaking,normal metal/insulator/ferromagnetic metal/dx_(2-y2)+is-wave superconductor(NM/I/FM/dx_(2-y2)+is-wave SC)and NM/I/FM/dx_(...The tunneling conductance of two kinds of tunnel junctions with time-reversal symmetry breaking,normal metal/insulator/ferromagnetic metal/dx_(2-y2)+is-wave superconductor(NM/I/FM/dx_(2-y2)+is-wave SC)and NM/I/FM/dx_(2-y2)+idxy-wave SC,is calculated using the extended Blonder-Tinkham-Klapwijk theoretical method.The ratio of the subdominant s-wave and dxy-wave components to the dominant dx_(2-y2)-wave component is expressed byΔ_(s)/Δ_(D)andΔ_(d)/Δ_(D),respectively.Results show that for NM/I/FM/dx_(2-y2)+is-wave SC tunnel junctions,the splitting of the zero-bias conductance peak(ZBCP)is obtained and the splitting peaks appear at eV/Δ_(0)=±Δ_(s)/Δ_(D)with eV the applied bias voltage andΔ_(0)the zero temperature energy gap of SC.For NM/I/FM/dx_(2-y2)+idxy-wave SC tunnel junctions,there are also conductance peaks at eV/Δ_(0)=±Δ_(d)/Δ_(D)but the ZBCP does not split.For the two types of tunnel junctions,the completely reversed tunnel conductance spectrum indicates that when the exchange energy in FM is increased to a certain value,the proximity effect transforms the tunnel junctions from the'0 state'to the'πstate'.The shortening of the transport quasiparticle lifetime can weaken the proximity effect to smooth out the dips and peaks in the tunnel spectrum.This is considered a possible reason that the ZBCP splitting was not observed in some previous experiments.It is expected that these analysis results can serve as a guide for future experiments and the relevant conclusions can be confirmed.展开更多
Lysine acetylation is one of the most prevalent and important posttranslational modifications(PTMs) in proteins. The process can be recognized by bromodomains(BRDs), which are a class of proteininteraction modules inv...Lysine acetylation is one of the most prevalent and important posttranslational modifications(PTMs) in proteins. The process can be recognized by bromodomains(BRDs), which are a class of proteininteraction modules involved in chromatin remodeling and transcriptional activation. The development of BRD fluorescent probes will be useful for monitoring the activity of BRDs in living cells as well as aiding inhibitor development. Herein we designed a peptide-based probe based on the proximity-induced protein conjugation reaction. The peptide-based probe is capable of covalently and selectively reacting with the unique cysteine residue in the bromodomain through proximity effect. Our experimental data showed that the probe displayed noticeable fluorescence response upon addition of BRD4(1). In-gel fluorescence scanning demonstrated that BRD4(1) can be covalently labelled by the probe. Moreover, the probe was shown to selectively detect BRD4(1) over other proteins. We envision that the probe developed in this study will provide a useful tool to further investigate the biological roles of BRDs.展开更多
基金supported by the Young Project of the Education Department in Guizhou Province(No.2022099)the Natural Science Special of Guizhou University(No.X202220 Special Post A).
文摘Ru-based nanomaterials have been demonstrated to be highly active electrocatalysts for hydrogen evo-lution reaction(HER),yet weak water adsorption and splitting ability in neutral media thus it is rather difficult for the intermediates to adsorb on the active site.Herein,we introduce a concept of the prox-imity effect,com prising adjacent Ru and RuO_(2) nanoparticles coupled on TiO_(2)(Ru/RuO_(2)-TiO_(2)),for the synergic promotion of water molecule adsorption and splitting,significantly enhancing HER electrocatal-ysis performance.The in-situ spectroscopy experiments and density function theory(DFT)simulations demonstrated that the proximity effect between the adjacent Ru nanoparticles and RuO_(2) nanoparticles can accelerate water adsorption and splitting.As a result,the as-made Ru/RuO_(2)-TiO_(2) only need overpo-tentials of 52.7,16.0,and 16.4 mV to achieve the current density of 10 mA cm-2 in neutral,acid,and alkaline media,respectively.The mass activity of Ru/RuO_(2)-TiO_(2) in neutral media is 320 and 117 times higher than that of commercial Ru/C and Pt/C at the overpotential of 100 mV,respectively.This work emphasizes the proximity effect for activation of reactants which can be extended to other electrocat-alytic reactions.
基金The work is supported by the National Key Research and Development Program of China(Grant No.2022YFA1204104)the National Natural Science Foundation of China(Grant No.61888102)the Chinese Academy of Sciences(Grant Nos.ZDBS-SSW-WHC001 and XDB33030100).
文摘Two-dimensional(2D)magnet/superconductor heterostructures can promote the design of artificial materials for exploring 2D physics and device applications by exotic proximity effects.However,plagued by the low Curie temperature and instability in air,it is hard to realize practical applications for the reported layered magnetic materials at present.In this paper,we developed a space-confined chemical vapor deposition method to synthesize ultrathin air-stable ε-Fe_(2)O_(3) nanosheets with Curie temperature above 350 K.The ε-Fe_(2)O_(3)/NbSe_(2) heterojunction was constructed to study the magnetic proximity effect on the superconductivity of the NbSe_(2) multilayer.The electrical transport results show that the subtle proximity effect can modulate the interfacial spin–orbit interaction while undegrading the superconducting critical parameters.Our work paves the way to construct 2D heterojunctions with ultrathin nonlayered materials and layered van der Waals(vdW)materials for exploring new physical phenomena.
文摘A new method for determining proximity parameters α,β ,and η in electron beam lithography is introduced on the assumption that the point exposure spread function is composed of two Gaussians.A single line is used as test pattern to determine proximity effect parameters and the normalization approach is adopted in experimental data transaction in order to eliminate the need of measuring exposure clearing dose of the resist.Furthermore,the parameters acquired by this method are successfully used for proximity effect correction in electron beam lithography on the same experimental conditions.
文摘We present a detailed routing algorithm considering the optical proximity effect. The light intensity is calculated beforehand and stored in look-up tables. These costs are used as a constraint to guide the sequential routing. The routing algorithm is based on constructed force directed Steiner tree routing to enhance routing efficien- cy. Experimental results on industrial benchmark circuits show that the presented routing algorithm can obtain much improvement considering optical effects short runtime.
基金the National Natural Science Foundation of China(No.20704042)the Shanghai Pujiang Talent Plan(No.07PJ14095)+1 种基金the CAS Knowledge Innovation Programthe Committee of Science and Technology of Shanghai(Nos.06XD14020,07JC14058,0752nm016)~~
文摘We describe the fabrication of metal nanogaps of sub-20nm in feature size using the proximity effect in electron beam lithography （EBL）. The proximity effect is extended to develop a flexible and practical method for preparing metal （e. g. Au or Ag） nanogaps and arrays in combination with a transfer process （e. g., deposition/lift-off）. Different from the direct gap-writing process,the nanogap precursor structures （nanoconnections） were designed by GDSII software and then written by electron beam. Following a deposition and lift-off process, the metal nanogaps were obtained and the nanogap size can be lowered to -10nm by controlling the exposure dose in EBL.
基金supported by National Natural Science Foundation of China(Nos.22108200,21938008 and 22121004)Natural Science Foundation of Zhejiang Province(LQ22B060013)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘The interaction between a promoter and an active metal crucially impacts catalytic performance.Nowadays,the influence of promoter contents and species has been intensively considered.In this study,we investigate the effect of the iron(Fe)-zinc(Zn)proximity of Fe-Zn bimetallic catalysts on CO_(2)hydrogenation performance.To eliminate the size effect,Fe_(2)O_(3)and ZnO nanoparticles with uniform size are first prepared by the thermal decomposition method.By changing the loading sequence or mixing method,a series of Fe-Zn bimetallic catalysts with different Fe-Zn distances are obtained.Combined with a series of characterization techniques and catalytic performances,Fe-Zn bimetallic proximity for compositions of Fe species is discussed.Furthermore,we observe that a smaller Fe-Zn distance inhibits the reduction and carburization of the Fe species and facilitates the oxidation of carbides.Appropriate proximity of Fe and Zn(i.e.,Fe_1Zn_(1)-imp and Fe_(1)Zn_(1)-mix samples)results in a suitable ratio of the Fe_5C_(2)and Fe_(3)O_(4)phases,simultaneously promoting the reverse water-gas shift and Fischer-Tropsch synthesis reactions.This study provides insight into the proximity effect of bimetallic catalysts on CO_(2)hydrogenation performance.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52022029,91850116,51772084,62090035,and U19A2090)Hunan Provincial Natural Science Foundation of China(Grant Nos.2018RS3051 and 2018WK4004)the Key Program of the Hunan Provincial Science and Technology Department(Grant No.2019XK2001).
文摘Two-dimensional(2D)magnetic materials have aroused tremendous interest due to the 2D confinement of magnetism and potential applications in spintronic and valleytronic devices.However,most of the currently 2D magnetic materials are achieved by the exfoliation from their bulks,of which the thickness and domain size are difficult to control,limiting the practical device applications.Here,we demonstrate the realization of thickness-tunable rhombohedral Cr_(2)Se_(3)nanosheets on different substrates via the chemical vapor deposition route.The magnetic transition temperature at about 75 K is observed.Furthermore,van der Waals heterostructures consisting of Cr_(2)Se_(3)nanosheets and monolayer WS2 are constructed.We observe the magnetic proximity effect in the heterostructures,which manifests the manipulation of the valley polarization in monolayer WS2.Our work contributes to the vapor growth and applications of 2D magnetic materials.
基金supported by the National Natural Science Foundation of China (Grant Nos. 91021019, 51074151, and 11034006)the National Basic Research Program of China (Grant Nos. 2010CB923401 and 2011CB921801)+2 种基金USDOE (Grant No. DE-FG03-02ER45958)US National Science Foundation (Grant No. 0906025)the BES Program of US Department of Energy (Grant No. ER45958)
文摘Topological insulators （Tls） are bulk insulators that possess robust helical conducting states along their interfaces with conventional insulators. A tremendous research effort has recently been devoted to TI-based heterostructures, in which con- ventional proximity effects give rise to a series of exotic physical phenomena. This paper reviews our recent studies on the potential existence of topological proximity effects at the interface between a topological insulator and a normal insu- lator or other topologically trivial systems. Using first-principles approaches, we have realized the tunability of the vertical location of the topological helical state via intriguing dual-proximity effects. To further elucidate the control parameters of this effect, we have used the graphene-based heterostructures as prototypical systems to reveal a more complete phase diagram. On the application side of the topological helical states, we have presented a catalysis example, where the topo- logical helical state plays an essential role in facilitating surface reactions by serving as an effective electron bath, These discoveries lay the foundation for accurate manipulation of the real space properties of the topological helical state in TI- based heterostructures and pave the way for realization of the salient functionality of topological insulators in future device applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11774434, 11974431, and 11832019)supported by National Supercomputer Center in Guangzhou。
文摘Recently, two-dimensional van der Waals(vd W) magnetic heterostructures have attracted intensive attention since they can show remarkable properties due to the magnetic proximity effect. In this work, the spin-polarized electronic structures of antimonene/Fe_(3)GeTe_(2)vdW heterostructures were investigated through the first-principles calculations. Owing to the magnetic proximity effect, the spin splitting appears at the conduction-band minimum(CBM) and the valence-band maximum(VBM) of the antimonene. A low-energy effective Hamiltonian was proposed to depict the spin splitting. It was found that the spin splitting can be modulated by means of applying an external electric field, changing interlayer distance or changing stacking configuration. The spin splitting energy at the CBM monotonously increases as the external electric field changes from-5 V/nm to 5 V/nm, while the spin splitting energy at the VBM almost remains the same. Meanwhile,as the interlayer distance increases, the spin splitting energies at the CBM and VBM both decrease. The different stacking configurations can also induce different spin splitting energies at the CBM and VBM. Our work demonstrates that the spin splitting of antimonene in this heterostructure is not singly dependent on the nearest Sb–Fe distance, which indicates that magnetic proximity effect in heterostructures may be modulated by multiple factors, such as hybridization of electronic states and the local electronic environment. The results enrich the fundamental understanding of the magnetic proximity effect in two-dimensional vdW heterostructures.
基金Project supported by the Natural Science Foundation of Education Bureau of Jiangsu Province, China （Grant No 05KJB140008）, and the Program for Excellent Talents in Huaiyin Teachers College, China.Acknowledgment We are especially grateful to Professor D. Y. Xing for pointing out the problem in this paper.
文摘We extend the Blonder, Tinkham and Klapwijk （BTK） theory to the study of the coexistence between ferromagnetism and s-wave superconductivity in ferromagnet/superconductor （F/S） structures. It is found that the ferromagnetism and s-wave superconductivity can coexist near the F/S interface, which is induced by proximity effects. On the F side, the density of states （DOS） exhibits some superconducting-like properties, and it displays a damped oscillation from ‘0＇ to ‘v＇ states with increasing either the thickness of F film or the exchange energy. We also study the influences of the spin-polarized exchange splitting in the F and the spin-degeneracy by Rashba spin-orbit coupling （RSOC） in the two-dimensional electron gas （2DGE） on the proximity effects. It is shown that the case of Rashba spin-degeneracy is very different from that of the spin-polarized exchange splitting.
基金Supported by the National Key Research and Development Program of China (Grant No.2016YFA0300600)the National Natural Science Foundation of China (Grant No.11961141011)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)。
文摘We report an experimental study of electron transport properties of MnSe/(Bi,Sb)_(2)Te_(3) heterostructures,in which MnSe is an antiferromagnetic insulator,and(Bi,Sb)_(2)Te_(3) is a three-dimensional topological insulator(TI).Strong magnetic proximity effect is manifested in the measurements of the Hall effect and longitudinal resistances.Our analysis shows that the gate voltage can substantially modify the anomalous Hall conductance,which exceeds 0.1 e^(2)/h at temperature T=1.6 K and magnetic field _(μ0)H=5 T,even though only the top TI surface is in proximity to MnSe.This work suggests that heterostructures based on antiferromagnetic insulators provide a promising platform for investigating a wide range of topological spintronic phenomena.
文摘We analyse the proximity effect in hybrid nanoscale junctions involving superconducting leads. We develop a general framework for the analysis of the proximity effect using the same theoretical methods typically employed for the analysis of conductance properties. We apply our method to a normal-superconductor tunnel contact and compare our results to previous results.
基金supported by the China National Key R&D Program(Grant No.2022YFA1504000)National Natural Science Foundation of China(Grant No.12474235)+2 种基金Tianjin Natural Science Foundation(Grant No.20JCZDJC00750)Tianjin Graduate Research and Innovation Project(Grant No.2021YJSB015)the Fundamental Research Funds for the Central Universities,Nankai University(Grant No.63211107,63201182,63221009,and 63231157).
文摘Proximity-induced magnetic exchange interactions offer a novel approach to manipulate the valley degree of freedom(DOF)in nonmagnetic monolayers without external magnetic fields.Transition metal dichalcogenides(TMDs)serve as an ideal platform for valleytronics research.Here,by introducing a twodimensional(2D)magnetic substrate,chromium germanium telluride(CrGeTe_(3)),we demonstrate effective control over the spin and valley properties of CrGeTe_(3)/MTe_(2)(M=Mo,W)van der Waals(vdW)heterostructures.Our first-principles calculations and k·p model Hamiltonian analysis reveal that the magnetic proximity effect(MPE)induces valley splitting and polarization in monolayer MoTe_(2)and WTe_(2)through the synergistic action of spin-orbit coupling(SOC)and proximity exchange interactions.Further investigation shows that valley splitting in these heterostructures is highly sensitive to the overlap between the atomic projection positions of TMDs and the magnetic Cr atoms,and can be continuously adjusted by varying the magnetization of CrGeTe_(3).Additionally,normal strain and experimentally accessible electric fields can effectively modulate the proximity exchange coupling,thus enabling extensive tunability of valley splitting.These controllable manipulations of the valley DOF through external stimuli mark a significant advancement in valleytronics,paving the way for next-generation electronic devices with enhanced performance and novel functionalities.
文摘Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon dioxide emissions.However,high hydrogenation energy barrier for*NO intermediates and insufficient supply of active hydrogen cause slow hydrogenation process,and further result in low efficiency of nitrate conversion and ammonia synthesis.Herein,a series of tandem catalysts,one-dimensional coordination polymers(1D CCPs)with dual sites are synthesized and obtained 190.4 mg h^(-1)mgcat^(-1)ammonia production rate with Faradaic efficiency of 97.16%,outperforming to the most of recent reported catalysts.The catalytic performances are well-maintained even after a long-term stability test of 1200 h,laying the foundation for practical applications.Density functional theory results reveal that the stationary adsorbed*NO on Ni site induced proximity electronic effect could reduce the energy barrier for hydrogenation of*NO intermediates over Cu site.In addition,the Ni site in the dual sites 1D CCPs is conducive to generating active hydrogen,providing rich proton source to boost the hydrogenation of*NO,and further enhancing the compatibility of deoxygenation and hydrogenation process.Our work paves a new insight into the mechanism of NITRR process and will inspire more research interests in exploring the proximity electronic effect in catalytic process.
基金J.Zhang gratefully acknowledges the financial support from the China Scholarship Council(No.202206120136).
文摘Recent studies have shown that the construction of nanophononic metamaterials can reduce thermal conductivity without affecting electrical properties,making them promising in many fields of application,such as energy conversion and thermal management.However,although extensive studies have been carried out on thermal conductivity reduction in nanophononic metamaterials,the local heat flux characteristic is still unclear.In this work,we construct a heat flux regulator which includes a silicon nanofilm with silicon pillars.The regulator has remarkable heat flux regulation ability,and various impacts on the regulation ability are explored.Surprisingly,even in the region without nanopillars,the local heat current is still lower than that in pristine silicon nanofilms,reduced by the neighboring nanopillars through the thermal proximity effect.We combine the analysis of the phonon participation ratio with the intensity of localized phonon modes to provide a clear explanation.Our findings not only provide insights into the mechanisms of heat flux regulation by nanophononic metamaterials,but also will open up new research directions to control local heat flux for a broad range of applications,including heat management,thermoelectric energy conversion,thermal cloak,and thermal concentrator.
基金Project supported by the National Key R&D Program of China(Grant Nos.2021YFA1400100 and 2024YFA1409700)the National Natural Science Foudation of China(Grant Nos.12374168 and T2325026)。
文摘Spin-orbit interaction(SOI)can be introduced by the proximity effect to modulate the electronic properties of graphene-based heterostructures.In this work,we stack trilayer WSe_(2) on Bernal tetralayer graphene to investigate the influence of SOI on the anomalous Hall effect(AHE).In this structurally asymmetric device,by comparing the magnitude of AHE at positive and negative displacement fields,we find that AHE is strongly enhanced by bringing electrons in proximity to the WSe_(2) layer.Meanwhile,the enhanced AHE signal persists up to 80 K,providing important routes for topological device applications at high temperatures.
基金Project supported by the National Natural Science Foundation of China(Nos.60506017,60776059)the National High Technology Research and Development Program of China(No.2007AA03Z303).
文摘A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography.The sizes of exposed patterns depend on dose factors while other exposure parameters（including accelerate voltage,resist thickness,exposing step size,substrate material,and so on） remain constant.This method is based on two reasonable assumptions in the evaluation of the compensated dose factor：one is that the relation between dose factors and circle-diameters is linear in the range under consideration;the other is that the compensated dose factor is only affected by the nearest neighbors for simplicity.Four-layer-hexagon photonic crystal structures were fabricated as test patterns to demonstrate this method.Compared to the uncorrected structures,the homogeneity of the corrected hole-size in photonic crystal structures was clearly improved.
基金supported by the National Natural Science Foundation of China(Nos.21977075,22271200)the National Key R&D Program of China(Nos.2022YFC2009902,2022YFC2009900)+1 种基金the Science and Technology Plan Project of Sichuan Province(No.2023YFS0121)the 1·3·5 Project for Disciplines of Excellence at West China Hospital(No.ZYYC23003),Sichuan University。
文摘Here,we present a novel bioorthogonal platform that enables precise positioning of attached moieties in close proximity,thereby facilitating the discovery and optimization of biocompatible reactions.Using this platform,we achieve a Horner-Wadsworth-Emmons(HWE)reaction under physiological conditions,generating a fluorophore in situ with a yield of up to 93%.This proximity platform should facilitate the discovery of various types of biocompatible reactions,making it a versatile tool for biomedical applica-tions.
基金supported by the Fundamental Research Funds for the Central Universities(Grant Nos.23CX03016A and 24CX030009A)。
文摘The tunneling conductance of two kinds of tunnel junctions with time-reversal symmetry breaking,normal metal/insulator/ferromagnetic metal/dx_(2-y2)+is-wave superconductor(NM/I/FM/dx_(2-y2)+is-wave SC)and NM/I/FM/dx_(2-y2)+idxy-wave SC,is calculated using the extended Blonder-Tinkham-Klapwijk theoretical method.The ratio of the subdominant s-wave and dxy-wave components to the dominant dx_(2-y2)-wave component is expressed byΔ_(s)/Δ_(D)andΔ_(d)/Δ_(D),respectively.Results show that for NM/I/FM/dx_(2-y2)+is-wave SC tunnel junctions,the splitting of the zero-bias conductance peak(ZBCP)is obtained and the splitting peaks appear at eV/Δ_(0)=±Δ_(s)/Δ_(D)with eV the applied bias voltage andΔ_(0)the zero temperature energy gap of SC.For NM/I/FM/dx_(2-y2)+idxy-wave SC tunnel junctions,there are also conductance peaks at eV/Δ_(0)=±Δ_(d)/Δ_(D)but the ZBCP does not split.For the two types of tunnel junctions,the completely reversed tunnel conductance spectrum indicates that when the exchange energy in FM is increased to a certain value,the proximity effect transforms the tunnel junctions from the'0 state'to the'πstate'.The shortening of the transport quasiparticle lifetime can weaken the proximity effect to smooth out the dips and peaks in the tunnel spectrum.This is considered a possible reason that the ZBCP splitting was not observed in some previous experiments.It is expected that these analysis results can serve as a guide for future experiments and the relevant conclusions can be confirmed.
基金the financial support from the National Natural Science Foundation of China (No. 21572190)the Hong Kong Early Career Scheme Grant (No. 21300714)the City University of Hong Kong Grant (No. 9667147)
文摘Lysine acetylation is one of the most prevalent and important posttranslational modifications(PTMs) in proteins. The process can be recognized by bromodomains(BRDs), which are a class of proteininteraction modules involved in chromatin remodeling and transcriptional activation. The development of BRD fluorescent probes will be useful for monitoring the activity of BRDs in living cells as well as aiding inhibitor development. Herein we designed a peptide-based probe based on the proximity-induced protein conjugation reaction. The peptide-based probe is capable of covalently and selectively reacting with the unique cysteine residue in the bromodomain through proximity effect. Our experimental data showed that the probe displayed noticeable fluorescence response upon addition of BRD4(1). In-gel fluorescence scanning demonstrated that BRD4(1) can be covalently labelled by the probe. Moreover, the probe was shown to selectively detect BRD4(1) over other proteins. We envision that the probe developed in this study will provide a useful tool to further investigate the biological roles of BRDs.
