The ability to control transport behaviors in nanostructure is crucial for usage as a fundamental research platform as well as a practical device.In this study,we report a gate-controlled crossover of electron transpo...The ability to control transport behaviors in nanostructure is crucial for usage as a fundamental research platform as well as a practical device.In this study,we report a gate-controlled crossover of electron transport behaviors using graphene nanoconstrictions as a platform.The observed transport properties span from Coulomb blockade-dominated single electron transmission to electron-wave interference-dominated quantum behavior.Such drastic modulation is achieved by utilizing a single back gate on a graphene nanoconstriction structure,where the size of nanostructure in the constriction and coupling strength of it to the electrodes can be tuned electrically.Our results indicate that electrostatic field by gate voltage upon the confined nanostructure defines both the size of the nanoconstriction as well as its interaction to electrodes.Increasing gate voltage raises Fermi level to cross the energy profile in the nanoconstriction,resulting in decreased energy barriers which affect the size of nanoconstriction and transmissivity of electrons.The gate-tunable nanoconstriction device can therefore become a potential platform to study quantum critical behaviors and enrich electronic and spintronic devices.展开更多
Interference of light and material particles is described with a unified model which does not need to assume the wave-particle duality. A moving particle is associated with a region of spatial correlated points named ...Interference of light and material particles is described with a unified model which does not need to assume the wave-particle duality. A moving particle is associated with a region of spatial correlated points named coherence cone. Its geometry depends on photon or particle momentum and on the parameters of the experimental setup. The final interference pattern is explained as a spatial distribution of particles caused by the coherence cone geometry. In the present context, the wave front superposition principle, wave-particle duality and wave-collapse lose their meaning. Fits of observed single electron and single molecule interference patterns together with the simulation of expected near-field molecule interference (Talbot carpet) demonstrate the model validity.展开更多
Electronic properties of multi-defected zigzag single-walled carbon nanotubes are investigated by use of the tight-binding Green's function method.The Stone-Wales defects and the vacancies are considered.We find t...Electronic properties of multi-defected zigzag single-walled carbon nanotubes are investigated by use of the tight-binding Green's function method.The Stone-Wales defects and the vacancies are considered.We find that the conductance sensitively depends on the realistic defect configurations for the metallic zigzag carbon nanotubes.Interestingly,the electronic transport properties of the nanotubes with three vacancies can be considered as the sum effect of two double-vacancies,while those with Stone-Wales defects can not.The electron interference along the longitudinal axis and the transport blocking are observed,which may be useful for understanding the electron transport behavior of carbon nanotube in experiments.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2016YFA0200800)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB07030100)the Sinopec Innovation Scheme(Grant No.A-527).
文摘The ability to control transport behaviors in nanostructure is crucial for usage as a fundamental research platform as well as a practical device.In this study,we report a gate-controlled crossover of electron transport behaviors using graphene nanoconstrictions as a platform.The observed transport properties span from Coulomb blockade-dominated single electron transmission to electron-wave interference-dominated quantum behavior.Such drastic modulation is achieved by utilizing a single back gate on a graphene nanoconstriction structure,where the size of nanostructure in the constriction and coupling strength of it to the electrodes can be tuned electrically.Our results indicate that electrostatic field by gate voltage upon the confined nanostructure defines both the size of the nanoconstriction as well as its interaction to electrodes.Increasing gate voltage raises Fermi level to cross the energy profile in the nanoconstriction,resulting in decreased energy barriers which affect the size of nanoconstriction and transmissivity of electrons.The gate-tunable nanoconstriction device can therefore become a potential platform to study quantum critical behaviors and enrich electronic and spintronic devices.
文摘Interference of light and material particles is described with a unified model which does not need to assume the wave-particle duality. A moving particle is associated with a region of spatial correlated points named coherence cone. Its geometry depends on photon or particle momentum and on the parameters of the experimental setup. The final interference pattern is explained as a spatial distribution of particles caused by the coherence cone geometry. In the present context, the wave front superposition principle, wave-particle duality and wave-collapse lose their meaning. Fits of observed single electron and single molecule interference patterns together with the simulation of expected near-field molecule interference (Talbot carpet) demonstrate the model validity.
基金supported by the Ministry of Science and Technology of Chinathe Ministry of Education of Chinathe National Natural Science Foundation of China
文摘Electronic properties of multi-defected zigzag single-walled carbon nanotubes are investigated by use of the tight-binding Green's function method.The Stone-Wales defects and the vacancies are considered.We find that the conductance sensitively depends on the realistic defect configurations for the metallic zigzag carbon nanotubes.Interestingly,the electronic transport properties of the nanotubes with three vacancies can be considered as the sum effect of two double-vacancies,while those with Stone-Wales defects can not.The electron interference along the longitudinal axis and the transport blocking are observed,which may be useful for understanding the electron transport behavior of carbon nanotube in experiments.
