由Rashba效应和横向自旋轨道耦合诱发的量子点接触中的0.7反常结构研究

本文研究了在非对称限制势下由Rashba效应和横向自旋-轨道耦合诱发的量子点接触系统中的反常量子输运行为. 研究发现，在一定范围的Rashba相互作用强度下, 电导在0.8×2e2/h附近有一个较弱的坪台. 该坪台电导的值与非对称限制势的偏压有关. 在某个范围的偏压下, 它会随着偏压的增大而减小. 另外, 由于Rashba自旋-轨道耦合效应, 在非对称限制势作用下电子将会自旋极化. 因此, 在没有任何外加磁场的情况下, 采用纯电学手段即可做成量子点接触自旋偏振器.

Investigations of 0.7 anomaly due to Rashba effect and lateral spin-orbit coupling in the quantum point contacts

We study the abnormal quantum transport through quantum point contact systems with Rashba effect and lateral spin-orbit coupling under asymmetric confinement geometries. We find that for a certain range of Rashba interaction strength, the conductance has a weak plateau around 0.8×2e^2/h. The value of this anomalous plateau is dependent on the voltage bias of the asymmetric confinement. We find that for a certain range of voltage bias, this weak plateau is lowered slightly with increasing the voltage bias. Furthermore, we find that the asymmetric confinement gives rises to a nonzero spin polarization due to the Rashba spin-orbit coupling. Therefore, we can make such quantum point contact spin-polarizer by purely electrical means in the absence of any applied external magnetic field.