Electron transport through a triple-terminal double-quantum-dot structure is theoretically studied. By adjusting the chemical potential in leads, two channels in this system are created, and in the presence of magneti...Electron transport through a triple-terminal double-quantum-dot structure is theoretically studied. By adjusting the chemical potential in leads, two channels in this system are created, and in the presence of magnetic flux the conductances for the two channels present remarkable difference from each other. When the quantum dots are made of ferromagnetic materials, the levels of quantum dots are spin dependent, then spin polarization comes about in the two channels. Furthermore, in some regions spin polarization in the different channels are opposite. We consider that this model can be a device prototype for spin filtering and spin separation.展开更多
The electromagnetically induced reflection(EIR)effect of graphene metamaterials has been investigated by finite difference time domain(FDTD)method.In this study,a metamaterial sandwich structure composed of silica(SiO...The electromagnetically induced reflection(EIR)effect of graphene metamaterials has been investigated by finite difference time domain(FDTD)method.In this study,a metamaterial sandwich structure composed of silica(SiO2),gold and graphene on terahertz band is designed.By changing the width of the two ribbons of graphene length and the incident angle of electromagnetic wave,the EIR effect of the structure is discussed,and it can be found that SiO2 is a kind of excellent dielectric material.The simulation results show that graphene metamaterial is not sensitive to polarized incident electromagnetic wave.Therefore,such EIR phenomena as insensitive polarization and large incident angle can be applied to optical communication filters and terahertz devices.展开更多
Highly crystalline and thermally stable pure multi-walled Ni3Si2O5（OH）4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200-210 ℃ using a facile and simple metho...Highly crystalline and thermally stable pure multi-walled Ni3Si2O5（OH）4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200-210 ℃ using a facile and simple method. The nickel ions between the layers could be reduced in situ to form size-tunable Ni nanocrystals, which endowed these nanotubes with tunable magnetic properties. Additionally, when used as the anode material in a lithium ion battery, the layered structure of the Ni3Si2O5（OH）4 nanotubes provided favorable transport kinetics for lithium ions and the discharge capacity reached 226.7 mA.h.g-1 after 21 cycles at a rate of 20 mA.g-1, Furthermore, after the nanotubes were calcined （600 ℃, 4 h） or reduced （180℃ 10 h）, the corresponding discharge capacities increased to 277.2 mA.h.g-1 and 308.5 mA.h.g-1, respectively.展开更多
文摘Electron transport through a triple-terminal double-quantum-dot structure is theoretically studied. By adjusting the chemical potential in leads, two channels in this system are created, and in the presence of magnetic flux the conductances for the two channels present remarkable difference from each other. When the quantum dots are made of ferromagnetic materials, the levels of quantum dots are spin dependent, then spin polarization comes about in the two channels. Furthermore, in some regions spin polarization in the different channels are opposite. We consider that this model can be a device prototype for spin filtering and spin separation.
基金Research Project of Anhui Province Education Department(No.KJ2020A0684)Innovation and Entrepreneurship Training Program for College Students(Nos.S201910375072,201910375050,201910375052,202010375030)。
文摘The electromagnetically induced reflection(EIR)effect of graphene metamaterials has been investigated by finite difference time domain(FDTD)method.In this study,a metamaterial sandwich structure composed of silica(SiO2),gold and graphene on terahertz band is designed.By changing the width of the two ribbons of graphene length and the incident angle of electromagnetic wave,the EIR effect of the structure is discussed,and it can be found that SiO2 is a kind of excellent dielectric material.The simulation results show that graphene metamaterial is not sensitive to polarized incident electromagnetic wave.Therefore,such EIR phenomena as insensitive polarization and large incident angle can be applied to optical communication filters and terahertz devices.
基金This work was supported by the Natural Science Foundation of China （No. 20725102）, the Fok Ying Tung Education Foundation （No. 111012）, and the State Key Project of Fundamental Research for Nanoscience and Nanotechnology （Nos. 2011CB932402, 2007CB310501, and 2011CB935704）.
文摘Highly crystalline and thermally stable pure multi-walled Ni3Si2O5（OH）4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200-210 ℃ using a facile and simple method. The nickel ions between the layers could be reduced in situ to form size-tunable Ni nanocrystals, which endowed these nanotubes with tunable magnetic properties. Additionally, when used as the anode material in a lithium ion battery, the layered structure of the Ni3Si2O5（OH）4 nanotubes provided favorable transport kinetics for lithium ions and the discharge capacity reached 226.7 mA.h.g-1 after 21 cycles at a rate of 20 mA.g-1, Furthermore, after the nanotubes were calcined （600 ℃, 4 h） or reduced （180℃ 10 h）, the corresponding discharge capacities increased to 277.2 mA.h.g-1 and 308.5 mA.h.g-1, respectively.
