It is commonly known that the hydrodynamic equations can be derived from the Boltzmann equation. In this paper, we derive similar spin-dependent balance equations based on the spinor Boltzmann equation. Besides the us...It is commonly known that the hydrodynamic equations can be derived from the Boltzmann equation. In this paper, we derive similar spin-dependent balance equations based on the spinor Boltzmann equation. Besides the usual charge current, heat current, and pressure tensor, we also explore the characteristic spin accumulation and spin current as well as the spin-dependent pressure tensor and heat current in spintronics. The numerical results of these physical quantities are demonstrated using an example of spin-polarized transport through a mesoscopic ferromagnet.展开更多
Macroscopic polarization differences in crystal dielectrics have been accurately treated by certain authors using the geometric phase approach.However,in their treatments the explicit meaning of the slowly varying par...Macroscopic polarization differences in crystal dielectrics have been accurately treated by certain authors using the geometric phase approach.However,in their treatments the explicit meaning of the slowly varying parameters was not explored.In this paper we restudy the problem under the Born-Oppenheimer approximation.It turns out that the coordinates of nuclei in the system can be taken as the slowly varying parameters.In addition,our treatment is no longer restricted to the case of null electric held.展开更多
A description of geometric phase in terms of path integral formalism is presented.It is proved that this adiabatic phase can appear in the propagator or Green function of an adiabatic system.In the semiclassical appro...A description of geometric phase in terms of path integral formalism is presented.It is proved that this adiabatic phase can appear in the propagator or Green function of an adiabatic system.In the semiclassical approximation,following the Green function expression of the electronic density of states,the corresponding generalized Bohr-Sommerfeld quantisation rule can thus be obtained.It is shown that this rule has been corrected by the geometric phase.展开更多
In order to consider quantum transport under the influence of an electron-electron （e-e） interaction in a mesoscopic conductor,the Boltzmann equation and Poisson equation are investigated jointly.The analytical expr...In order to consider quantum transport under the influence of an electron-electron （e-e） interaction in a mesoscopic conductor,the Boltzmann equation and Poisson equation are investigated jointly.The analytical expressions of the distribution function for the Boltzmann equation and the self-consistent average potential concerned with e-e interaction are obtained,and the dielectric function appearing in the self-consistent average potential is naturally generalized beyond the Thomas-Fermi approximation.Then we apply these results to the tunneling junctions of a metal-insulator-semiconductor （MIS） in which the electrons are accumulated near the interface of the semiconductor,and we find that the e-e interaction plays an important role in the transport procedure of this system. The electronic density,electric current as well as screening Coulombic potential in this case are studied,and we reveal the time and position dependence of these physical quantities explicitly affected by the e-e interaction.展开更多
We study the magnetization reversal of single-molecular magnets by a spin-polarized current in the framework of the spinor Boltzmann equation.Because of the spin–orbit coupling,the spin-polarized current will impose ...We study the magnetization reversal of single-molecular magnets by a spin-polarized current in the framework of the spinor Boltzmann equation.Because of the spin–orbit coupling,the spin-polarized current will impose a non-zero spin transfer torque on the single-molecular magnets,which will induce the magnetization switching of the latter.Via the s–d exchange interaction between the conducting electrons and single-molecular magnets,we can investigate the magnetization dynamics of single-molecular magnets.We demonstrate the dynamics of the magnetization based on the spin diffusion equation and the Heisenberg-like equation.The results show that when the current is large enough,the magnetization of the single-molecular magnets can be reversed.We also calculate the critical current density required for the magnetization reversal under different anisotropy and external magnetic fields,which is helpful for the corresponding experimental design.展开更多
Based on both the spin diffusion equation and the Landau-LlTshitz-Gilbert （LLG） equation, we demonstrate the influence of out-of-plane spin torque on magnetization switching and susceptibility in a magnetic multilay...Based on both the spin diffusion equation and the Landau-LlTshitz-Gilbert （LLG） equation, we demonstrate the influence of out-of-plane spin torque on magnetization switching and susceptibility in a magnetic multilayer system. The variation of spin accumulation and local magnetization with respect to time are studied in the magnetization reversal induced by spin torque. We also research the susceptibility subject to a microwave magnetic field, which is compared with the results obtained without out-of-plane torque.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11274378)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB08-3)the MOST of China(Grant No.2013CB933401)
文摘It is commonly known that the hydrodynamic equations can be derived from the Boltzmann equation. In this paper, we derive similar spin-dependent balance equations based on the spinor Boltzmann equation. Besides the usual charge current, heat current, and pressure tensor, we also explore the characteristic spin accumulation and spin current as well as the spin-dependent pressure tensor and heat current in spintronics. The numerical results of these physical quantities are demonstrated using an example of spin-polarized transport through a mesoscopic ferromagnet.
基金Supported by the National Natural Science Foundation of China under Grant No.19677101.
文摘Macroscopic polarization differences in crystal dielectrics have been accurately treated by certain authors using the geometric phase approach.However,in their treatments the explicit meaning of the slowly varying parameters was not explored.In this paper we restudy the problem under the Born-Oppenheimer approximation.It turns out that the coordinates of nuclei in the system can be taken as the slowly varying parameters.In addition,our treatment is no longer restricted to the case of null electric held.
基金Supported by the National Natural Science Foundation of China under Grant No.19677101.
文摘A description of geometric phase in terms of path integral formalism is presented.It is proved that this adiabatic phase can appear in the propagator or Green function of an adiabatic system.In the semiclassical approximation,following the Green function expression of the electronic density of states,the corresponding generalized Bohr-Sommerfeld quantisation rule can thus be obtained.It is shown that this rule has been corrected by the geometric phase.
基金Project supported by the National Natural Science Foundation of China (Grant No 10404037)
文摘In order to consider quantum transport under the influence of an electron-electron （e-e） interaction in a mesoscopic conductor,the Boltzmann equation and Poisson equation are investigated jointly.The analytical expressions of the distribution function for the Boltzmann equation and the self-consistent average potential concerned with e-e interaction are obtained,and the dielectric function appearing in the self-consistent average potential is naturally generalized beyond the Thomas-Fermi approximation.Then we apply these results to the tunneling junctions of a metal-insulator-semiconductor （MIS） in which the electrons are accumulated near the interface of the semiconductor,and we find that the e-e interaction plays an important role in the transport procedure of this system. The electronic density,electric current as well as screening Coulombic potential in this case are studied,and we reveal the time and position dependence of these physical quantities explicitly affected by the e-e interaction.
基金Supported by the National Key R&D Program of China(Grant No.2018YFA0305804)the National Natural Science Foundation of China(Grant No.11834014the Strategetic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB28000000).
文摘We study the magnetization reversal of single-molecular magnets by a spin-polarized current in the framework of the spinor Boltzmann equation.Because of the spin–orbit coupling,the spin-polarized current will impose a non-zero spin transfer torque on the single-molecular magnets,which will induce the magnetization switching of the latter.Via the s–d exchange interaction between the conducting electrons and single-molecular magnets,we can investigate the magnetization dynamics of single-molecular magnets.We demonstrate the dynamics of the magnetization based on the spin diffusion equation and the Heisenberg-like equation.The results show that when the current is large enough,the magnetization of the single-molecular magnets can be reversed.We also calculate the critical current density required for the magnetization reversal under different anisotropy and external magnetic fields,which is helpful for the corresponding experimental design.
基金Supported in part by the National Natural Science Foundation of China under Grant No 10404037. We thank Yan Qing-Bo and Gong Shou-Shu for helpful discussion, and Su Gang and Zheng Qing-Rong for valuable suggestions.
文摘Based on both the spin diffusion equation and the Landau-LlTshitz-Gilbert （LLG） equation, we demonstrate the influence of out-of-plane spin torque on magnetization switching and susceptibility in a magnetic multilayer system. The variation of spin accumulation and local magnetization with respect to time are studied in the magnetization reversal induced by spin torque. We also research the susceptibility subject to a microwave magnetic field, which is compared with the results obtained without out-of-plane torque.
