A model for theoretical analysis of nonlinear (or high gain) mode of photoconductive semiconductor switches (PCSS's) is proposed.The switching transition of high gain PCSS's can be described with an optically...A model for theoretical analysis of nonlinear (or high gain) mode of photoconductive semiconductor switches (PCSS's) is proposed.The switching transition of high gain PCSS's can be described with an optically activated charge domain. The switching characteristics including rise time,delay and their relationship to electric field strength,optical trigger energies are discussed.The formation and radiation transit,accumulation of the charge domain are related with the triggering and sustaining phases of PCSS's,respectively.The results of the mathematical model on this mechanism agree with experimental results.展开更多
Recent experimental advances have uncovered fractional Chern insulator(FCI)states in twisted MoTe_(2)(tMoTe_(2))systems under zero magnetic field.Understanding the interaction effects on topological phases within real...Recent experimental advances have uncovered fractional Chern insulator(FCI)states in twisted MoTe_(2)(tMoTe_(2))systems under zero magnetic field.Understanding the interaction effects on topological phases within realistic model presents a significant theoretical challenge.Here,we construct a moirésuperlattice model tailored for tMoTe_(2)and conduct investigations using state-of-the-art tensor-network methods.Our ground-state calculations reveal a rich variety of interaction-driven and filling-dependent topological phases,including FCIs,Chern insulators,and generalized Wigner crystals,which are revealed in recent experiments.For FCI state,dynamical simulations uncover a single-particle excitation continuum with a finite charge gap,reflecting the fractionalized charge excitations.Finite-temperature calculations further determine characteristic charge activation and ferromagnetic transition temperatures,reconciling existing experimental discrepancies.Furthermore,using this realistic lattice model,we predict the presence of quantum anomalous Hall crystals exhibiting integer Hall conductivity at fractional fillings in tMoTe_(2).By integrating ground-state,finite-temperature,and dynamical analyses,our work establishes a comprehensive framework for understanding correlated topological phases in tMoTe_(2)and related moirésystems.展开更多
Interfacial charge transfer and active sites play important roles in the performance of heterogeneousphotocatalysts. Reticular chemistry in covalent organic frameworks (COFs) allows the construction of isomericarchite...Interfacial charge transfer and active sites play important roles in the performance of heterogeneousphotocatalysts. Reticular chemistry in covalent organic frameworks (COFs) allows the construction of isomericarchitectures made of different donor and acceptor monomers for tuning the charge transferdynamics and active sites. Herein, five D-A dual-pore COFs were prepared from the reaction of naphthalene-2,6-diamine (electron donor) with different tetraaldehyde electron acceptors. Experimental resultsdisclosed that linker engineering, by changing the conjugation systems using heteroatoms of benzooxadiazole,benzothiadiazole, benzoselenadiazole, naphthothiadiazole, and naphthoselenadiazole, tuned theelectron-accepting capacity of the corresponding D-A COFs. Among the five samples, the naphthothiadiazole-derived COF demonstrated optimal charge transfer and active sites, exhibiting the highest hydrogenevolution rate of ca. 35 mmol g^(-1) h^(-1) in the presence of 3 wt% Pt under visible-light irradiation(>420 nm). This work illustrates linker engineering as a strategy for the simultaneous adjustment of interfacialcharge transfer and active sites to enhance the hydrogen generation efficiency, offering new vigorto develop the COF photocatalysts on the basis of reticular synthesis.展开更多
Iontronics presents a transformative paradigm for energy and information processing via ions as active charge carriers.Here,triboiontronics is introduced,a novel strategy leveraging contact electrification to achieve ...Iontronics presents a transformative paradigm for energy and information processing via ions as active charge carriers.Here,triboiontronics is introduced,a novel strategy leveraging contact electrification to achieve dynamic regulation of electrical double layers.Inspired by signaling mechanisms of biological neural systems,triboiontronics enables enhanced ionic-electronic coupling without external power input,offering a material-independent and self-powered pathway for programmable interfacial behavior,underscoring its promise for post-Moore,energy-autonomous information technologies.展开更多
A 4 mm gap semi-insulating （SI） GaAs photoconductive switch （PCSS） was triggered by a pulse laser with a wavelength of 1064 nm and a pulse energy of 0.5 mJ. In the experiment, when the bias field was 4 kV, the swi...A 4 mm gap semi-insulating （SI） GaAs photoconductive switch （PCSS） was triggered by a pulse laser with a wavelength of 1064 nm and a pulse energy of 0.5 mJ. In the experiment, when the bias field was 4 kV, the switch did not induce self-maintained discharge but worked in nonlinear （lock-on） mode. The phenomenon is analyzed as follows： an exciton effect contributes to photoconduction in the generation and dissociation of ex- citons. Collision ionization, avalanche multiplication and the exciton effect can supply carrier concentration and energy when an outside light source was removed. Under the combined influence of these factors, the S1-GaAs PCSS develops into self-maintained discharge rather than just in the light-controlled prebreakdown status. The characteristics of the filament affect the degree of damage to the switch.展开更多
文摘A model for theoretical analysis of nonlinear (or high gain) mode of photoconductive semiconductor switches (PCSS's) is proposed.The switching transition of high gain PCSS's can be described with an optically activated charge domain. The switching characteristics including rise time,delay and their relationship to electric field strength,optical trigger energies are discussed.The formation and radiation transit,accumulation of the charge domain are related with the triggering and sustaining phases of PCSS's,respectively.The results of the mathematical model on this mechanism agree with experimental results.
基金supported by the National Natural Science Foundation of China(12222412 and 12047503)the National Key Projects for Research and Development of China(2024YFA1409200)+3 种基金the Innovation Program for Quantum Science and Technology(2021ZD0301900)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB1270100)the Postdoctoral Fellowship Program of CPSF(GZB20240772)We thank the HPC-ITP for the technical support and generous allocation of CPU time.Xiaoyu Wang acknowledges financial support from the National High Magnetic Field Laboratory through National Science Foundation(NSF)(DMR-2128556),and the State of Florida.
文摘Recent experimental advances have uncovered fractional Chern insulator(FCI)states in twisted MoTe_(2)(tMoTe_(2))systems under zero magnetic field.Understanding the interaction effects on topological phases within realistic model presents a significant theoretical challenge.Here,we construct a moirésuperlattice model tailored for tMoTe_(2)and conduct investigations using state-of-the-art tensor-network methods.Our ground-state calculations reveal a rich variety of interaction-driven and filling-dependent topological phases,including FCIs,Chern insulators,and generalized Wigner crystals,which are revealed in recent experiments.For FCI state,dynamical simulations uncover a single-particle excitation continuum with a finite charge gap,reflecting the fractionalized charge excitations.Finite-temperature calculations further determine characteristic charge activation and ferromagnetic transition temperatures,reconciling existing experimental discrepancies.Furthermore,using this realistic lattice model,we predict the presence of quantum anomalous Hall crystals exhibiting integer Hall conductivity at fractional fillings in tMoTe_(2).By integrating ground-state,finite-temperature,and dynamical analyses,our work establishes a comprehensive framework for understanding correlated topological phases in tMoTe_(2)and related moirésystems.
基金supported by the Natural Science Foundation of China(No.22261132512,22235001,22175020,and 22131005)Xiaomi Young Scholar Program,and University of Science and Technology Beijing.
文摘Interfacial charge transfer and active sites play important roles in the performance of heterogeneousphotocatalysts. Reticular chemistry in covalent organic frameworks (COFs) allows the construction of isomericarchitectures made of different donor and acceptor monomers for tuning the charge transferdynamics and active sites. Herein, five D-A dual-pore COFs were prepared from the reaction of naphthalene-2,6-diamine (electron donor) with different tetraaldehyde electron acceptors. Experimental resultsdisclosed that linker engineering, by changing the conjugation systems using heteroatoms of benzooxadiazole,benzothiadiazole, benzoselenadiazole, naphthothiadiazole, and naphthoselenadiazole, tuned theelectron-accepting capacity of the corresponding D-A COFs. Among the five samples, the naphthothiadiazole-derived COF demonstrated optimal charge transfer and active sites, exhibiting the highest hydrogenevolution rate of ca. 35 mmol g^(-1) h^(-1) in the presence of 3 wt% Pt under visible-light irradiation(>420 nm). This work illustrates linker engineering as a strategy for the simultaneous adjustment of interfacialcharge transfer and active sites to enhance the hydrogen generation efficiency, offering new vigorto develop the COF photocatalysts on the basis of reticular synthesis.
基金supported by the National Natural Science Foundation(grant number 22479016).
文摘Iontronics presents a transformative paradigm for energy and information processing via ions as active charge carriers.Here,triboiontronics is introduced,a novel strategy leveraging contact electrification to achieve dynamic regulation of electrical double layers.Inspired by signaling mechanisms of biological neural systems,triboiontronics enables enhanced ionic-electronic coupling without external power input,offering a material-independent and self-powered pathway for programmable interfacial behavior,underscoring its promise for post-Moore,energy-autonomous information technologies.
基金Project supported by the National Natural Science Foundation of China(Nos.50837005,10876026)the State Key Laboratory of Electrical Insulation for Power Equipment(No.EIPE09203).
文摘A 4 mm gap semi-insulating （SI） GaAs photoconductive switch （PCSS） was triggered by a pulse laser with a wavelength of 1064 nm and a pulse energy of 0.5 mJ. In the experiment, when the bias field was 4 kV, the switch did not induce self-maintained discharge but worked in nonlinear （lock-on） mode. The phenomenon is analyzed as follows： an exciton effect contributes to photoconduction in the generation and dissociation of ex- citons. Collision ionization, avalanche multiplication and the exciton effect can supply carrier concentration and energy when an outside light source was removed. Under the combined influence of these factors, the S1-GaAs PCSS develops into self-maintained discharge rather than just in the light-controlled prebreakdown status. The characteristics of the filament affect the degree of damage to the switch.
