We theoretically study the influence of the $k$-cubic Rashba spin-orbit coupling (SOC) on the correlation effects of magnetic impurities by combining the variational method and the Hirsch-Fye quantum Monte Carlo (HFQMC) simulations. Markedly different from the normal $k$-linear Rashba SOC, even a small cubic Rashba term can greatly alter the band structure and induce a Van Hove singularity in a wide range of energy, thus the single impurity local moment becomes largely tunable. The cubic Rashba SOC adopted in this work breaks the rotational symmetry, but the host material is still invariant under the operations $\mathcal{R}^z(π)$, $\mathcal{IR}^z(π/2)$, $\mathcal{M}_{xz}$, $\mathcal{M}_{yz}$, where $\mathcal{R}^z(θ)$ is the rotation of angle $θ$ about the $z$-axis, $\mathcal{I}$ is the inversion operator and $\mathcal{M}_{xz}$ ($\mathcal{M}_{yz}$) is the mirror reflection about the $x$-$z$ ($y$-$z$) principal plane. Saliently, various components of spin-spin correlation between the single magnetic impurity and the conduction electrons show three- or six-fold rotational symmetry. This unique feature is due to the triple winding of the spins with a $2π$ rotation of $\mathbf{k}$, which is a hallmark of the cubic Rashba effect and can possibly be an identifier to distinguish the cubic Rashba SOC from the normal $k$-linear Rashba term in experiments. Although the cubic Rashba term drastically alters the electronic properties of the host, we find that the spatial decay rate of the spin-spin correlation function remains essentially unchanged. Moreover, the carrier-mediated Ruderman-Kittel-Kasuya-Yosida interactions between two magnetic impurities show twisted features, the ferromagnetic diagonal terms dominate when two magnetic impurities are very close, but the off-diagonal terms become important at long distances.
Spontaneous nonreciprocal transport in a gate-tunable ferromagnetic Rashba 2-dimensional electron gas
Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay（阿尔贝·费尔特实验室，法国国家科学研究中心，泰雷兹集团，巴黎萨克雷大学）；Helmholtz-Zentrum Berlin（柏林赫尔姆霍兹中心）；Institut für Physik, Martin-Luther-Universität, Halle-Wittenberg（马丁·路德哈勒-维滕贝格大学物理研究所）；Plateforme Mesures Physiques à Basses Températures, Sorbonne Université（索邦大学低温测量平台）；Saha Institute of Nuclear Physics（萨哈核物理研究所）；Max Planck Institute of Microstructure Physics（马克斯·普朗克微结构物理研究所）
Topological Flat Minibands and Fractional Chern Insulators in Rashba Systems with Tunable Superlattice Potentials
University of Science and Technology of China（中国科学技术大学）；International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China（中国科学技术大学合肥微尺度物质科学国家研究中心量子功能材料国际中心）；Hefei National Laboratory, University of Science and Technology of China（中国科学技术大学合肥国家实验室）
Robust gapless surface state and Rashba-splitting bands upon surface deposition of magnetic Cr on Bi$_2$Se$_3$
磁性杂质与无带隙表面态之间的相互作用对于在拓扑绝缘体中实现新的量子现象和新的功能是至关重要的。通过结合角度分辨光电子能谱实验和密度泛函理论计算，我们发现Cr原子在Bi $_2$ Se $_3$表面的沉积不会导致狄拉克点处表面态的能隙打开，表明在我们的测量温度15 K下不存在长程面外铁磁性.这与体Cr掺杂形成鲜明对比，并且起源归因于不同的Cr占据位点。这些结果突出了掺杂磁性杂质的纳米级结构在决定拓扑绝缘体的电子和磁性方面的重要性。
The role of band-index-dependent transport relaxation times in anomalous Hall effect
我们重新回顾了反常霍尔效应（AHE）的模型计算，并表明，在具有点状势杂质的各向同性Rashba耦合二维电子气（2DEG）中，半经典Boltzmann方程（SBE）的完全解可能不同于广泛使用的$1/τ^{||}$和$1/τ^{\perp}$解[Phys. Rev. B 68，165311（2003）]。我们对AHE的方法类似于各向异性磁阻的基于SBE的分析，导致分布函数的积分方程[Phys.Rev.B79，045427（2009）]，但在本例中，我们将描述简化为带折射率相关的输运弛豫时间。当两个Rashba带都被部分占据时，这些通过求解线性方程组来确定。详细的计算表明，对于本征散射和混合斜散射，当费米能级较大时，$1/τ^{||}$和$1/τ^{\perp}$与SBE完全解的差别是显著的。对于坐标偏移效应，在带间弹性散射过程中获得的侧跳速度被证明是更重要的较大的Rashba耦合，甚至可能超过带内的外部Rashba带。在所考虑的情况下，坐标位移对AHE的贡献显着不同于之前分析的光滑无序势的限制。
