Covariant Conservation Laws and the Spin Hall Effect in Dirac-Rashba Systems.
Covariant Conservation Laws and the Spin Hall Effect in Dirac-Rashba Systems.
复制标题
DOI：
10.1103/physrevlett.119.246801
复制
发表时间：
2017-05
影响因子：
8.6
通讯作者：
M. Milletarí;Manuel Offidani;Aires Ferreira;R. Raimondi
中科院分区：
文献类型：
--
作者：
M. Milletarí;Manuel Offidani;Aires Ferreira;R. Raimondi
我们提出了一个理论分析的二维Dirac-Rashba系统中存在的障碍和外部扰动。我们揭示了一组精确的对称关系（沃德恒等式），施加强约束狄拉克费米子的自旋动力学受到邻近诱导的相互作用。这使我们能够证明，一个任意稀释浓度的标量杂质的非平衡自旋霍尔电流的总抑制时，只有Rashba自旋轨道耦合存在的结果。值得注意的是，一个有限的自旋霍尔电导率恢复时，最小的Dirac-Rashba模型补充了自旋谷相互作用。沃德恒等式提供了一个系统的方法来预测出现的自旋霍尔效应在更广泛的类的实验相关的Dirac-Rashba系统，并代表了一个重要的基准测试的有效性数值方法。
We present a theoretical analysis of two-dimensional Dirac-Rashba systems in the presence of disorder and external perturbations. We unveil a set of exact symmetry relations (Ward identities) that impose strong constraints on the spin dynamics of Dirac fermions subject to proximity-induced interactions. This allows us to demonstrate that an arbitrary dilute concentration of scalar impurities results in the total suppression of nonequilibrium spin Hall currents when only Rashba spin-orbit coupling is present. Remarkably, a finite spin Hall conductivity is restored when the minimal Dirac-Rashba model is supplemented with a spin-valley interaction. The Ward identities provide a systematic way to predict the emergence of the spin Hall effect in a wider class of Dirac-Rashba systems of experimental relevance and represent an important benchmark for testing the validity of numerical methodologies.