Electron doping has been established as an effective method to enhance the superconducting transition temperature and superconducting energy gap of FeSe thin films on strontium titanate(SrTiO_(3))substrates.Previous s...Electron doping has been established as an effective method to enhance the superconducting transition temperature and superconducting energy gap of FeSe thin films on strontium titanate(SrTiO_(3))substrates.Previous studies have demonstrated that electron/hole doping can be achieved through the adsorption of metal phthalocyanine(MPc,M=Co,Cu,Mn,Fe,and Ni)molecules on surfaces.This work explores the electron doping induced by the adsorption of MPc molecules,specifically cobalt phthalocyanine(CoPc)and copper phthalocyanine(CuPc),onto FeSe monolayer and multilayers.Utilizing first-principles calculations based on density functional theory,we demonstrate that charge rearrangement occurs when MPc molecules adsorb on the FeSe substrate,contributing to an accumulation of electrons at the interface.In the CoPc/FeSe systems,the electron accumulation increases with the layer number of FeSe substrate,converging for substrates with 3-5 layers.The analysis of the integrated planar charge difference up to the position with zero integrated charge transfer reveals that all the five MPc molecules donate electrons to the uppermost FeSe layer.The electron donation suggests that MPc adsorption can be a promising strategy to modulate the superconductivity of FeSe layers.展开更多
By using scanning tunneling microscopy,we investigated the electronic evolution of T_(d)-WTe_(2) via in-situ surface alkali K atoms deposition.The T_(d)-WTe_(2) surface is electron doped upon K deposition,and as the K...By using scanning tunneling microscopy,we investigated the electronic evolution of T_(d)-WTe_(2) via in-situ surface alkali K atoms deposition.The T_(d)-WTe_(2) surface is electron doped upon K deposition,and as the K coverage increases,two gaps are sequentially opened near Fermi energy,which probably indicates that two phase transitions concomitantly occur during electron doping.The two gaps both show a dome-like dependence on the K coverage.While the bigger gap shows no prominent dependence on the magnetic field,the smaller one can be well suppressed and thus possibly corresponds to the superconducting transition.This work indicates that T_(d)-WTe_(2) exhibits rich quantum states closely related to the carrier concentration.展开更多
Atomic intercalation in two-dimensional （2D） layered materials can be used to engineer the electronic structure at the atomic scale and generate tuneable physical and chemical properties which are quite distinct in ...Atomic intercalation in two-dimensional （2D） layered materials can be used to engineer the electronic structure at the atomic scale and generate tuneable physical and chemical properties which are quite distinct in comparison with the pristine material. Among them, electron-doped engineering induced by intercalation is an efficient route to modulate electronic states in 2D layers. Herein, we demonstrate a semiconducting to metallic phase transition in zirconium diselenide （ZrSe2） single crystals via controllable incorporation of copper （Cu） atoms. Our angle resolved photoemission spectroscopy （ARPES） measurements and first-principles density functional theory （DFT） calculations dearly revealed the emergence of conduction band dispersion at the M/L point of the Brillouin zone due to Cu-induced electron doping in ZrSe2 interlayers. Moreover, electrical measurements in ZrSe2 revealed semiconducting behavior, while the Cu-intercalated ZrSe2 exhibited a linear current-voltage curve with metallic character. The atomic intercalation approach may have high potential for realizing transparent electron-doping systems for many specific 2D-based nanoelectronic applications.展开更多
The electronic transport properties of a molecular junction based on doping tailoring armchair-type graphene nanoribbons（AGNRs）with different widths are investigated by applying the non-equilibrium Green＇s function...The electronic transport properties of a molecular junction based on doping tailoring armchair-type graphene nanoribbons（AGNRs）with different widths are investigated by applying the non-equilibrium Green＇s function formalism combined with first-principles density functional theory.The calculated results show that the width and doping play significant roles in the electronic transport properties of the molecular junction.A higher current can be obtained for the molecular junctions with the tailoring AGNRs with W=11.Furthermore,the current of boron-doped tailoring AGNRs with widths W=7 is nearly four times larger than that of the undoped one,which can be potentially useful for the design of high performance electronic devices.展开更多
By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the d...By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.展开更多
We investigate the electronic transport properties of dipyrimidinyl-diphenyl sandwiched between two armchair graphene nanoribbon electrodes using the nonequilibrium Green function formalism combined with a first-princ...We investigate the electronic transport properties of dipyrimidinyl-diphenyl sandwiched between two armchair graphene nanoribbon electrodes using the nonequilibrium Green function formalism combined with a first-principles method based on density functional theory. Among the three models M1–M3, M1 is not doped with a heteroatom. In the left parts of M2 and M3, nitrogen atoms are doped at two edges of the nanoribbon. In the right parts, nitrogen atoms are doped at one center and at the edges of M2 and M3, respectively. Comparisons of M1, M2 and M3 show obvious rectifying characteristics, and the maximum rectification ratios are up to 42.9 in M2. The results show that the rectifying behavior is strongly dependent on the doping position of electrodes. A higher rectification ratio can be found in the dipyrimidinyl-diphenyl molecular device with asymmetric doping of left and right electrodes, which suggests that this system has a broader application in future logic and memory devices.展开更多
Within the charge-spin separation fermion-spin theory, we show that themechanism of superconductivity in the electron doped cobaltate Na_x CoO_2 · gH_2O is ascribed toits kinetic energy. The dressed fermions inte...Within the charge-spin separation fermion-spin theory, we show that themechanism of superconductivity in the electron doped cobaltate Na_x CoO_2 · gH_2O is ascribed toits kinetic energy. The dressed fermions interact occurring directly through the kinetic energy byexchanging magnetic excitations. This interaction leads to a net attractive force between dressedfermions, then the electron Cooper pairs originating from the dressed fermion pairing state are dueto the charge-spin recombination, and their condensation reveals the superconducting ground state.The superconducting transition temperature is identical to the dressed fermion pair transitiontemperature, and is suppressed to a lower temperature due to the strong magnetic frustration. Theoptimal superconducting transition temperature occurs in the electron doping concentration δ ≈0.29, and then decreases for both underdoped and overdoped regimes, in qualitative agreement withthe experimental results.展开更多
Ga doped ZnO （OZO）/Cu grid/GZO transparent conductive electrode （TCE） structures were fabricated at room temperature （RT） by using electron beam evaporation （EBE） for the Cu grids and RF magnetron sputtering f...Ga doped ZnO （OZO）/Cu grid/GZO transparent conductive electrode （TCE） structures were fabricated at room temperature （RT） by using electron beam evaporation （EBE） for the Cu grids and RF magnetron sputtering for the GZO layers. In this work, we investigated the electrical and optical characteristics of GZO/Cu grid/GZO multilayer electrode for thin film solar cells by using evaporated Cu grid and sputtered GZO thin films to enhance the optical transparency without significantly affecting their conductivity. The optical transmittance and sheet resistance of GZO/Cu grid/GZO multilayer are higher than those of GZO/Cu film/GZO multilayer independent of Cu grid separation distance and increase with increasing Cu grid separation distances. The calculation of both transmittance and sheet resistance of GZO/Cu grid] GZO multilayer was based on Cu filling factor correlated with the geometry of Cu grid. The calculated values for the transmittance and sheet resistance of the GZO/Cu grid/GZO multilayer were similar to the experimentally observed ones. The highest figure of merit ФTc is 5.18× 10^-3Ω^-1 for the GZO/Cu grid] GZO multilayer with Cu grid separation distance of 1 mm was obtained, in this case, the transmittance and resistivity were 82.72% and 2.17 × 10 ^-4Ωcm, respectively. The transmittance and resistivity are accentahle for nractical thin film snlar cell annlicatinn~展开更多
To improve the electrochemical performances of α-MnO2 as electrode materials for supercapacitors, Sn-doped α-MnO2 in the presence of the doping amount of 1%-4% was successfully synthesized by hydrothermal method. As...To improve the electrochemical performances of α-MnO2 as electrode materials for supercapacitors, Sn-doped α-MnO2 in the presence of the doping amount of 1%-4% was successfully synthesized by hydrothermal method. As-prepared α-MnO2 presents nanorod shape and no other impurities exist. By ultraviolet-visible absorption spectroscopy, it is convinced that the band gaps of α-MnO2 decrease with increasing Sn-doping amount. Cyclic voltammetry investigation indicates that undoped and doped α-MnO2 all have regular capacitive response. As the scan rate enlarged, the profiles of curves gradually deviate from rectangle. Compared with undoped α-MnO2, doped α-MnO2 has larger specific capacitance. The specific capacitance of 3% doped α-MnO2 reaches 241.0 F/g while undoped α-MnO2 only has 173.0 F/g under 50 m A/g current density in galvanostatical charge-discharge measurement. Enhanced conductivity by Sn-doping is considered to account for doped sample＇s enhanced electrochemical specific capacitance.展开更多
The multiband superconductor offers a unique venue for investigating the interplay between Cooper pairing and inter-band interactions.Here we report the emergence of two-band superconductivity in hybridized superlatti...The multiband superconductor offers a unique venue for investigating the interplay between Cooper pairing and inter-band interactions.Here we report the emergence of two-band superconductivity in hybridized superlattice Na0.1(1,3-diaminopropane)0.25 ZrNCl.The intercalation of organic molecules and Na ions into the interlayer modulates the electronic structure near the Fermi surface,and promotes the emergence of intrinsic superconductivity with onset transition temperature T_(c)=15 K.Systematical investigations of upper critical field H_(c2)reveals that temperature dependence of H_(c2)can be well-described by two-band theory,yielding the out-of-plane and in-plane H_(c2)values of 2.9 T and 11.5 T,respectively.Furthermore,analysis of the reversible magnetization data confirms the intrinsic two-band characteristics,which deviate significantly from the predictions of the single-band Ginzburg-Landau(GL)model.Meanwhile,the superconducting state exhibits a two-fold rotational symmetry under in-plane magnetic fields,contrasting with the three-fold symmetric ZrNCl lattice.Angle-dependent H_(c2)behavior aligns with the three-dimensional(3D)anisotropic GL model.These findings establish the intercalated rhombohedral ZrNCl as a compelling platform for exploring multiband superconductivity.展开更多
The electrolyte-assisted exfoliation strategy is widely employed to synthesize ultrathin two-dimensional(2D)materials.Yet,spins in 2D magnets are susceptible to the electrolyte due to the underlying charge doping effe...The electrolyte-assisted exfoliation strategy is widely employed to synthesize ultrathin two-dimensional(2D)materials.Yet,spins in 2D magnets are susceptible to the electrolyte due to the underlying charge doping effect.Hence,it is crucial to understand and trace the doping process during the delamination of 2D magnets.Taking the prototype Fe_(3)GeTe_(2),we utilized soft organic cations to exfoliate the bulk and obtain a freestanding organ-ic–inorganic hybrid superlattice with a giant electron doping effect as high as 6.9×10^(14)/cm^(2)(~1.15 electrons per formula unit).A remarkable ferromagnetic transition exceeding 385 K was revealed in these superlattices,together with unique anisotropic saturation magnetization.The doping enhanced the in-plane electron–phonon coupling and thus optimized originally poor indirect double-exchange scenario for spin electrons.The emerging vertical magnetization shift phenomenon served to evaluate the uniformity of charge doping.The above findings provide a new perspective for understanding the role of parasitic charge in 2D magnetism.展开更多
Intercalation is an effective method to modify physical properties and induce novel electronic states of transition metal dichalcogenide(TMD)materials.However,it is difficult to reveal the microscopic electronic state...Intercalation is an effective method to modify physical properties and induce novel electronic states of transition metal dichalcogenide(TMD)materials.However,it is difficult to reveal the microscopic electronic state evolution in the intercalated TMDs.Here we successfully synthesize the copper-intercalated 1T-TaS_(2) and characterize the structural and electronic modification combining resistivity measurements,atomic-resolution scanning transmission electron microscopy(ADF-STEM),and scanning tunneling microscopy(STM).The intercalated Cu atom is determined to be directly below the Ta atom and suppresses the commensurate charge density wave(CCDW)phase.Two specific electronic modulations are discovered in the near-commensurate(NC)CDW phase:the electron doping state near the defective star of Davids(SDs)in metallic domains and the spatial evolution of the Mott gap in insulating domains.Both modulations reveal that intercalated Cu atoms act as a medium to enhance the interaction between intralayer SDs,in addition to the general charge transfer effect.It also solidifies the Mott foundation of the insulating gap in pristine samples.The intriguing electronic evolution in Cu-intercalated 1T-TaS_(2) will motivate further exploration of novel electronic states in the intercalated TMD materials.展开更多
Low-dimensional multiferroic metals characterized by the simultaneous coexistence of ferroelectricity,conductivity,and magnetism hold tremendous potential for scientific and technological endeavors.However,the mutuall...Low-dimensional multiferroic metals characterized by the simultaneous coexistence of ferroelectricity,conductivity,and magnetism hold tremendous potential for scientific and technological endeavors.However,the mutually exclusive mechanisms among these properties impede the discovery of multifunctional conducting multiferroics,especially at the atomic-scale.Here,based on first-principles calculations,we design and demonstrate intrinsic one-dimensional(1D)ferroelectrics and carrier dopinginduced metallic multiferroics in an atomicWOF4 wire.TheWOF4 atomic wire that can be derived from a 1D van derWaals crystal exhibits pronounced ferroelectricity manifested in the form of large cooperative atomic displacements.By performing Monte Carlo simulations with an effective Hamiltonian method,we obtain the nanowire that can sustain a high Curie temperature,indicating its potential for roomtemperature applications.Moreover,doping with electrons is found to induce magnetism and metallic conductivity that coexists with the ferroelectric distortion in the nanowire.These appealing properties in conjunction with the experimental feasibility enable the doped WOF4 nanowire to act as a promising atomic-scale multifunctional material.展开更多
The seeking of room temperature ferromagnetic semiconductors, which take advantages of both the charge and spin degrees of freedom of electrons to realize a variety of functionalities in devices integrated with electr...The seeking of room temperature ferromagnetic semiconductors, which take advantages of both the charge and spin degrees of freedom of electrons to realize a variety of functionalities in devices integrated with electronic, optical, and magnetic storage properties, has been a long-term goal of scientists and engi- neers. Here, by using the spin-polarized density functional theory calculations, we predict a new series of high temperature ferromagnetic semiconductors based on the melilite-type oxysulfide Sr2MnGe2S60 through hole （K） and electron （La） doping. Due to the lack of strong antiferromagnetic superexchange between Mn ions, the weak antiferromagnetic order in the parent compound Sr2MnGe2S60 can be sup- pressed easily by charge doping with either p-type magnetic order. At a doping concentration of or n-type carriers, giving rise to the expected ferro- 25%, both the hole-doped and electron-doped compounds can achieve a Curie temperature （To） above 300 K. The underlying mechanism is analyzed. Our study provides an effective approach for exploring new types of high temperature ferromagnetic semiconductors.展开更多
As the era of nanoelectronics is dawning,CNT（carbon nanotube）,a one-dimensional nano material with outstanding properties and performances,has aroused wide attention.In order to study its optical and electrical prop...As the era of nanoelectronics is dawning,CNT（carbon nanotube）,a one-dimensional nano material with outstanding properties and performances,has aroused wide attention.In order to study its optical and electrical properties,this paper has researched the influence of tension-twisting deformation,defects,and mixed type on the electronic structure and optical properties of the armchair carbon nanotube superlattices doped cyclic alternately with B and N by using the first-principle method.Our findings show that if tension-twisting deformation is conducted,then the geometric structure,bond length,binding energy,band gap and optical properties of B,N doped carbon nanotube superlattices with defects and mixed type will be influenced.As the degree of exerted tension-twisting deformation increases,B,N doped carbon nanotube superlattices become less stable,and B,N doped carbon nanotube superlattices with defects are more stable than that with exerted tension-twisting deformations.Proper tension-twisting deformation can adjust the energy gap of the system;defects can only reduce the energy gap,enhancing the system metallicity;while the mixed type of 5%tension,twisting angle of 15° and atomic defects will significantly increase the energy gap of the system.From the perspective of optical properties,doped carbon nanotubes may transform the system from metallicity into semi-conductivity.展开更多
基金support from the National Natural Science Foundation of China(Grant No.62488201)the National Key Research and Development Program of China(Grant No.2022YFA1204100).
文摘Electron doping has been established as an effective method to enhance the superconducting transition temperature and superconducting energy gap of FeSe thin films on strontium titanate(SrTiO_(3))substrates.Previous studies have demonstrated that electron/hole doping can be achieved through the adsorption of metal phthalocyanine(MPc,M=Co,Cu,Mn,Fe,and Ni)molecules on surfaces.This work explores the electron doping induced by the adsorption of MPc molecules,specifically cobalt phthalocyanine(CoPc)and copper phthalocyanine(CuPc),onto FeSe monolayer and multilayers.Utilizing first-principles calculations based on density functional theory,we demonstrate that charge rearrangement occurs when MPc molecules adsorb on the FeSe substrate,contributing to an accumulation of electrons at the interface.In the CoPc/FeSe systems,the electron accumulation increases with the layer number of FeSe substrate,converging for substrates with 3-5 layers.The analysis of the integrated planar charge difference up to the position with zero integrated charge transfer reveals that all the five MPc molecules donate electrons to the uppermost FeSe layer.The electron donation suggests that MPc adsorption can be a promising strategy to modulate the superconductivity of FeSe layers.
基金financially supported by the National Natural Science Foundation of China(Grants Nos.11790311,92165205,51902152,11874210,and 11774149)the National Key R&D Program of China(Grants No.2021YFA1400403)。
文摘By using scanning tunneling microscopy,we investigated the electronic evolution of T_(d)-WTe_(2) via in-situ surface alkali K atoms deposition.The T_(d)-WTe_(2) surface is electron doped upon K deposition,and as the K coverage increases,two gaps are sequentially opened near Fermi energy,which probably indicates that two phase transitions concomitantly occur during electron doping.The two gaps both show a dome-like dependence on the K coverage.While the bigger gap shows no prominent dependence on the magnetic field,the smaller one can be well suppressed and thus possibly corresponds to the superconducting transition.This work indicates that T_(d)-WTe_(2) exhibits rich quantum states closely related to the carrier concentration.
文摘Atomic intercalation in two-dimensional （2D） layered materials can be used to engineer the electronic structure at the atomic scale and generate tuneable physical and chemical properties which are quite distinct in comparison with the pristine material. Among them, electron-doped engineering induced by intercalation is an efficient route to modulate electronic states in 2D layers. Herein, we demonstrate a semiconducting to metallic phase transition in zirconium diselenide （ZrSe2） single crystals via controllable incorporation of copper （Cu） atoms. Our angle resolved photoemission spectroscopy （ARPES） measurements and first-principles density functional theory （DFT） calculations dearly revealed the emergence of conduction band dispersion at the M/L point of the Brillouin zone due to Cu-induced electron doping in ZrSe2 interlayers. Moreover, electrical measurements in ZrSe2 revealed semiconducting behavior, while the Cu-intercalated ZrSe2 exhibited a linear current-voltage curve with metallic character. The atomic intercalation approach may have high potential for realizing transparent electron-doping systems for many specific 2D-based nanoelectronic applications.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11004156 and 11547172the Science and Technology Star Project of Shaanxi Province under Grant No 2016KJXX-45
文摘The electronic transport properties of a molecular junction based on doping tailoring armchair-type graphene nanoribbons（AGNRs）with different widths are investigated by applying the non-equilibrium Green＇s function formalism combined with first-principles density functional theory.The calculated results show that the width and doping play significant roles in the electronic transport properties of the molecular junction.A higher current can be obtained for the molecular junctions with the tailoring AGNRs with W=11.Furthermore,the current of boron-doped tailoring AGNRs with widths W=7 is nearly four times larger than that of the undoped one,which can be potentially useful for the design of high performance electronic devices.
基金Supported by the National Basic Research Program of China(973 Program)under Grant Nos 2011CBA00106 and2012CB927400the National Natural Science Foundation of China under Grant Nos 11274332 and 11227902Helmholtz Association through the Virtual Institute for Topological Insulators(VITI).M.Y.Li and D.W.Shen are also supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB04040300
文摘By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11504283 and 21503153the Natural Science Foundation of Shaanxi Province under Grant No 2014JM1025the Science and Technology Star Project of Shaanxi Province under Grant No 2016KJXX-45
文摘We investigate the electronic transport properties of dipyrimidinyl-diphenyl sandwiched between two armchair graphene nanoribbon electrodes using the nonequilibrium Green function formalism combined with a first-principles method based on density functional theory. Among the three models M1–M3, M1 is not doped with a heteroatom. In the left parts of M2 and M3, nitrogen atoms are doped at two edges of the nanoribbon. In the right parts, nitrogen atoms are doped at one center and at the edges of M2 and M3, respectively. Comparisons of M1, M2 and M3 show obvious rectifying characteristics, and the maximum rectification ratios are up to 42.9 in M2. The results show that the rectifying behavior is strongly dependent on the doping position of electrodes. A higher rectification ratio can be found in the dipyrimidinyl-diphenyl molecular device with asymmetric doping of left and right electrodes, which suggests that this system has a broader application in future logic and memory devices.
文摘Within the charge-spin separation fermion-spin theory, we show that themechanism of superconductivity in the electron doped cobaltate Na_x CoO_2 · gH_2O is ascribed toits kinetic energy. The dressed fermions interact occurring directly through the kinetic energy byexchanging magnetic excitations. This interaction leads to a net attractive force between dressedfermions, then the electron Cooper pairs originating from the dressed fermion pairing state are dueto the charge-spin recombination, and their condensation reveals the superconducting ground state.The superconducting transition temperature is identical to the dressed fermion pair transitiontemperature, and is suppressed to a lower temperature due to the strong magnetic frustration. Theoptimal superconducting transition temperature occurs in the electron doping concentration δ ≈0.29, and then decreases for both underdoped and overdoped regimes, in qualitative agreement withthe experimental results.
基金support of the key project of the National Natural Science Foundation of China under Grant Nos.91333203 and 51172204the Program for Innovative Research Team in University of Ministry of Education of China under Grant No.IRT13037the Zhejiang Provincial Department of Science and Technology of China under Grant No.2010R50020
文摘Ga doped ZnO （OZO）/Cu grid/GZO transparent conductive electrode （TCE） structures were fabricated at room temperature （RT） by using electron beam evaporation （EBE） for the Cu grids and RF magnetron sputtering for the GZO layers. In this work, we investigated the electrical and optical characteristics of GZO/Cu grid/GZO multilayer electrode for thin film solar cells by using evaporated Cu grid and sputtered GZO thin films to enhance the optical transparency without significantly affecting their conductivity. The optical transmittance and sheet resistance of GZO/Cu grid/GZO multilayer are higher than those of GZO/Cu film/GZO multilayer independent of Cu grid separation distance and increase with increasing Cu grid separation distances. The calculation of both transmittance and sheet resistance of GZO/Cu grid] GZO multilayer was based on Cu filling factor correlated with the geometry of Cu grid. The calculated values for the transmittance and sheet resistance of the GZO/Cu grid/GZO multilayer were similar to the experimentally observed ones. The highest figure of merit ФTc is 5.18× 10^-3Ω^-1 for the GZO/Cu grid] GZO multilayer with Cu grid separation distance of 1 mm was obtained, in this case, the transmittance and resistivity were 82.72% and 2.17 × 10 ^-4Ωcm, respectively. The transmittance and resistivity are accentahle for nractical thin film snlar cell annlicatinn~
基金Funded by The National Natural Science Foundation of China(51402185)the Natural Science Foundation of Shanghai(13ZR1454700)
文摘To improve the electrochemical performances of α-MnO2 as electrode materials for supercapacitors, Sn-doped α-MnO2 in the presence of the doping amount of 1%-4% was successfully synthesized by hydrothermal method. As-prepared α-MnO2 presents nanorod shape and no other impurities exist. By ultraviolet-visible absorption spectroscopy, it is convinced that the band gaps of α-MnO2 decrease with increasing Sn-doping amount. Cyclic voltammetry investigation indicates that undoped and doped α-MnO2 all have regular capacitive response. As the scan rate enlarged, the profiles of curves gradually deviate from rectangle. Compared with undoped α-MnO2, doped α-MnO2 has larger specific capacitance. The specific capacitance of 3% doped α-MnO2 reaches 241.0 F/g while undoped α-MnO2 only has 173.0 F/g under 50 m A/g current density in galvanostatical charge-discharge measurement. Enhanced conductivity by Sn-doping is considered to account for doped sample＇s enhanced electrochemical specific capacitance.
基金supported by the National Key Basic Research and Development Program of China(grant no.2022YFA1403700,2024YFA1409100)the National Natural Science Foundation of China(12334002)+2 种基金Shenzhen Science and Technology Program(RCJC20200714114435105)Innovative Team of General Higher Educational Institutes in Guangdong Province(2020KCXTD001)supported by the Southern University of Science and Technology Core Research Facilities(SUStech CRF).
文摘The multiband superconductor offers a unique venue for investigating the interplay between Cooper pairing and inter-band interactions.Here we report the emergence of two-band superconductivity in hybridized superlattice Na0.1(1,3-diaminopropane)0.25 ZrNCl.The intercalation of organic molecules and Na ions into the interlayer modulates the electronic structure near the Fermi surface,and promotes the emergence of intrinsic superconductivity with onset transition temperature T_(c)=15 K.Systematical investigations of upper critical field H_(c2)reveals that temperature dependence of H_(c2)can be well-described by two-band theory,yielding the out-of-plane and in-plane H_(c2)values of 2.9 T and 11.5 T,respectively.Furthermore,analysis of the reversible magnetization data confirms the intrinsic two-band characteristics,which deviate significantly from the predictions of the single-band Ginzburg-Landau(GL)model.Meanwhile,the superconducting state exhibits a two-fold rotational symmetry under in-plane magnetic fields,contrasting with the three-fold symmetric ZrNCl lattice.Angle-dependent H_(c2)behavior aligns with the three-dimensional(3D)anisotropic GL model.These findings establish the intercalated rhombohedral ZrNCl as a compelling platform for exploring multiband superconductivity.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.62274050 and 91963123the Zhejiang Pro-vincial Natural Science Foundation of China under Grant No.LZ21E020002L.Hu acknowledges funding under grant No.SKL2020-03 from the State Key Laboratory of Silicon Materials.
文摘The electrolyte-assisted exfoliation strategy is widely employed to synthesize ultrathin two-dimensional(2D)materials.Yet,spins in 2D magnets are susceptible to the electrolyte due to the underlying charge doping effect.Hence,it is crucial to understand and trace the doping process during the delamination of 2D magnets.Taking the prototype Fe_(3)GeTe_(2),we utilized soft organic cations to exfoliate the bulk and obtain a freestanding organ-ic–inorganic hybrid superlattice with a giant electron doping effect as high as 6.9×10^(14)/cm^(2)(~1.15 electrons per formula unit).A remarkable ferromagnetic transition exceeding 385 K was revealed in these superlattices,together with unique anisotropic saturation magnetization.The doping enhanced the in-plane electron–phonon coupling and thus optimized originally poor indirect double-exchange scenario for spin electrons.The emerging vertical magnetization shift phenomenon served to evaluate the uniformity of charge doping.The above findings provide a new perspective for understanding the role of parasitic charge in 2D magnetism.
基金This work was supported by the National Key Research and Development Program(No.2019YFA0308602)the Key Research and Development Program of Zhejiang Province,China(No.2021C01002)+6 种基金Vacuum Interconnected Nanotech Workstation(Nano-X)(B2004)the Fundamental Research Funds for the Central Universities in ChinaD.D.and C.J.thank the National Natural Science Foundation of China(Nos.NSFC-51772265 and NSFC-61721005)J.G.,W.W.,X.L.,W.L.,and Y.S.thank the support of the National Key Research and Development Program(No.2016YFA0300404)the National Natural Science Foundation of China(Nos.NSFC-11674326 and NSFC-11874357)the Joint Funds of the National Natural Science Foundation of Chinathe Chinese Academy of Sciences’Large-scale Scientific Facility(Nos.U1832141,U1932217,and U2032215).
文摘Intercalation is an effective method to modify physical properties and induce novel electronic states of transition metal dichalcogenide(TMD)materials.However,it is difficult to reveal the microscopic electronic state evolution in the intercalated TMDs.Here we successfully synthesize the copper-intercalated 1T-TaS_(2) and characterize the structural and electronic modification combining resistivity measurements,atomic-resolution scanning transmission electron microscopy(ADF-STEM),and scanning tunneling microscopy(STM).The intercalated Cu atom is determined to be directly below the Ta atom and suppresses the commensurate charge density wave(CCDW)phase.Two specific electronic modulations are discovered in the near-commensurate(NC)CDW phase:the electron doping state near the defective star of Davids(SDs)in metallic domains and the spatial evolution of the Mott gap in insulating domains.Both modulations reveal that intercalated Cu atoms act as a medium to enhance the interaction between intralayer SDs,in addition to the general charge transfer effect.It also solidifies the Mott foundation of the insulating gap in pristine samples.The intriguing electronic evolution in Cu-intercalated 1T-TaS_(2) will motivate further exploration of novel electronic states in the intercalated TMD materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172370,11874059 and 12174405)Natural Science Foundation of Zhejiang Provincial(Grant Nos.LY22E020012 and LR19A040002)+1 种基金National Key R&D Program of China(Grant No.2022YFB3807601),the Key Research Project of Zhejiang Laboratory(Grant No.2021PE0AC02)Zhejiang Laboratory Open Research Project(Grant No.K2022PE0AB06)and JSPS International Research Fellow(No.P22065).
文摘Low-dimensional multiferroic metals characterized by the simultaneous coexistence of ferroelectricity,conductivity,and magnetism hold tremendous potential for scientific and technological endeavors.However,the mutually exclusive mechanisms among these properties impede the discovery of multifunctional conducting multiferroics,especially at the atomic-scale.Here,based on first-principles calculations,we design and demonstrate intrinsic one-dimensional(1D)ferroelectrics and carrier dopinginduced metallic multiferroics in an atomicWOF4 wire.TheWOF4 atomic wire that can be derived from a 1D van derWaals crystal exhibits pronounced ferroelectricity manifested in the form of large cooperative atomic displacements.By performing Monte Carlo simulations with an effective Hamiltonian method,we obtain the nanowire that can sustain a high Curie temperature,indicating its potential for roomtemperature applications.Moreover,doping with electrons is found to induce magnetism and metallic conductivity that coexists with the ferroelectric distortion in the nanowire.These appealing properties in conjunction with the experimental feasibility enable the doped WOF4 nanowire to act as a promising atomic-scale multifunctional material.
基金supported by the National Key Research and Development Program of China(2017YFA0302903)the National Natural Science Foundation of China(11774422 and 11774424)
文摘The seeking of room temperature ferromagnetic semiconductors, which take advantages of both the charge and spin degrees of freedom of electrons to realize a variety of functionalities in devices integrated with electronic, optical, and magnetic storage properties, has been a long-term goal of scientists and engi- neers. Here, by using the spin-polarized density functional theory calculations, we predict a new series of high temperature ferromagnetic semiconductors based on the melilite-type oxysulfide Sr2MnGe2S60 through hole （K） and electron （La） doping. Due to the lack of strong antiferromagnetic superexchange between Mn ions, the weak antiferromagnetic order in the parent compound Sr2MnGe2S60 can be sup- pressed easily by charge doping with either p-type magnetic order. At a doping concentration of or n-type carriers, giving rise to the expected ferro- 25%, both the hole-doped and electron-doped compounds can achieve a Curie temperature （To） above 300 K. The underlying mechanism is analyzed. Our study provides an effective approach for exploring new types of high temperature ferromagnetic semiconductors.
基金supported by the National Natural Science Foundation of China(No.51371049)the Natural Science Foundation of Liaoning Province(No.20102173)
文摘As the era of nanoelectronics is dawning,CNT（carbon nanotube）,a one-dimensional nano material with outstanding properties and performances,has aroused wide attention.In order to study its optical and electrical properties,this paper has researched the influence of tension-twisting deformation,defects,and mixed type on the electronic structure and optical properties of the armchair carbon nanotube superlattices doped cyclic alternately with B and N by using the first-principle method.Our findings show that if tension-twisting deformation is conducted,then the geometric structure,bond length,binding energy,band gap and optical properties of B,N doped carbon nanotube superlattices with defects and mixed type will be influenced.As the degree of exerted tension-twisting deformation increases,B,N doped carbon nanotube superlattices become less stable,and B,N doped carbon nanotube superlattices with defects are more stable than that with exerted tension-twisting deformations.Proper tension-twisting deformation can adjust the energy gap of the system;defects can only reduce the energy gap,enhancing the system metallicity;while the mixed type of 5%tension,twisting angle of 15° and atomic defects will significantly increase the energy gap of the system.From the perspective of optical properties,doped carbon nanotubes may transform the system from metallicity into semi-conductivity.
