arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1702.04887cond-mat.mes-hall
收藏

电子气中电流感生自旋极化理论

Theory of current-induced spin polarizations in an electron gas

Cosimo Gorini, Amin Maleki, Ka Shen, Ilya V. Tokatly, Giovanni Vignale, Roberto Raimondi

摘要:

本文导出了自旋轨道耦合下二维电子气自旋动力学的布洛赫方程。对于后者,我们认为这两个内在机制的结构反转不对称性(Rashba)和体反转不对称性(Dresselhaus),和杂质的散射所产生的外在的。推导基于Rashba-Dresselhaus自旋轨道耦合的SU(2)规范场公式。我们的主要结果是识别一个新的自旋产生扭矩所产生的Elliot-Yafet过程中,反对一个类似的条款所产生的Dyakonov-Perel过程。新的自旋产生扭矩有助于电流诱导自旋极化(CISP)-也称为Edelstein或逆自旋电流效应。因此,CISP的行为比单独考虑内部Rashba-Dresselhaus场所能想到的要复杂得多。特别是,电流引起的自旋极化的对称性不一定与内部Rashba-Dresselhaus场的对称性一致,并且通常预测CISP的面外分量,如在最近的实验中观察到的。我们还讨论了扩展到三维电子气,这可能是相关的解释实验中的薄膜。

英文摘要:

We derive the Bloch equations for the spin dynamics of a two-dimensional electron gas in the presence of spin-orbit coupling. For the latter we consider both the intrinsic mechanisms of structure inversion asymmetry (Rashba) and bulk inversion asymmetry (Dresselhaus), and the extrinsic ones arising from the scattering from impurities. The derivation is based on the SU(2) gauge-field formulation of the Rashba-Dresselhaus spin-orbit coupling. Our main result is the identification of a new spin-generation torque arising from the Elliot-Yafet process, which opposes a similar term arising from the Dyakonov-Perel process. The new spin-generation torque contributes to the current-induced spin polarization (CISP) -- also known as the Edelstein or inverse spin-galvanic effect. As a result, the behavior of the CISP turns out to be more complex than one would surmise from consideration of the internal Rashba-Dresselhaus fields alone. In particular, the symmetry of the current-induced spin polarization does not necessarily coincide with that of the internal Rashba-Dresselhaus field, and an out-of-plane component of the CISP is generally predicted, as observed in recent experiments. We also discuss the extension to the three-dimensional electron gas, which may be relevant for the interpretation of experiments in thin films.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑