利用紧束缚近似的非平衡格林函数法,研究了含Rashba和Dresselhaus自旋轨道耦合效应的双阶梯型量子线中电子的自旋电 导开关效应。结果表明在正向偏压下, 系统有大的自旋电导出现;但在反向偏压下, 这个大的自旋电导会消失。并且自旋电导 随着Rashba和Dresselhaus 自旋轨道耦合效应的变化呈现圆形结构, 表明Rashba和Dresselhaus自旋轨道耦合效应引起自旋 电导的作用是一样的, 因此可以通过调节Rashba或Dresselhaus自旋轨道耦合效应来控制自旋电导。该系统在未来有可能用来 制作全电自旋电导开关的量子线。

The electron spin conductance switch effect in a two step-likes quantum wire under the modulation of both the Rashba and Dresselhaus spin-orbit couplings (SOCs) is investigated by using the non-equilibrium Green’s function (NEGF) method with tight binding approximation scheme. Results show that a very large spin conductance occurs in the system under consideration when the electrons transport in the forward biased case, while the spin conductance vanishes when the electrons transport in the backward biased case. Moreover, it is found that the spin conductance of the system displays a“circular”profile according to the change of both the Rashba and Dresselhaus SOCs, which demonstrates that the two SOCs have the same effects on inducing spin conductance. Therefore, one can control the spin conductance of the system by tuning either the Rashba or Dresselhaus SOC strength, which indicates that the system can be utilized to make the proposed quantum wire with all-electrical spin conductance diode in the future.