Hall coefficient in amorphous alloys: critical behavior and quantitative test of quantum corrections due to weak localization and electron-electron interactions
在这里，我们提出了一系列的$Ti_xSi_{100-x}$无定形达到临界浓度，$x_c\approx9-9.5$的$R_H$的测量。对于$x\geq17$，霍尔系数显示了微扰理论预测的行为，$R_H^{-1}\left(T\right)=R_H^{-1}\left(0\right)+bT^{1/2}$，其延伸到150 K的温度。在具有较低$x$的合金中，温度依赖性变得更强; $R_H\left(0\right)$在$x_c$处发散，显示临界行为。我们用高钛含量合金的电导率和霍尔系数数据来检验电导率的量子修正理论。我们发现，由于弱局域化的校正是由电子-声子散射的速率随温度变化的$τ_{ep}^{-1}=A_{ep}T^2$占主导地位。所提取的参数$A_{ep}$与考虑晶格振动对杂质不完全拖曳的理论符合得很好。从弱局域化修正中提取的自旋-轨道散射时间比标准估计值$τ_{so}\approxτ\left(\hbar c/e^2Z\right)^4$给出的时间大两个数量级。利用Ti-Si和$\left(Ag_{0.5}Cu_{0.5}\right)_{100-x}Ge_x$非晶合金的Hall系数和比热数据对EEI量子修正理论进行了检验，这使我们能够估计理论所需的所有微观参数。我们发现，在我们的测量精度范围内，EEI理论完全适用于遵循自由电子模型的合金[ $\left(Ag_{0.5}Cu_{0.5}\right)_{100-x}Ge_x$ with $x\le50$]。在所有的Ti-Si合金和Ag-Cu-Ge合金中观察到的$x\geq60$与理论的偏差可以定性地解释为系统中的电子屏蔽减弱。
英文摘要：
Here, we present the measurements of $R_H$ in a series of $Ti_xSi_{100-x}$ amorphous reaching the critical concentration, $x_c\approx9-9.5$. For $x\geq17$, the Hall coefficient displays the behavior predicted by the perturbation theory, $R_H^{-1}\left(T\right)=R_H^{-1}\left(0\right)+bT^{1/2}$, which extends up to the temperature 150 K. The temperature dependence gets stronger in alloys with lower $x$; $R_H\left(0\right)$ diverges at $x_c$ displaying critical behavior. We used the combined conductivity and Hall coefficient data for alloys with high Ti content to test the theories of quantum corrections to conductivity. We found that the correction due to weak localization is dominated by the electron-phonon scattering with the rate varying with temperature as $τ_{ep}^{-1}=A_{ep}T^2$. The extracted parameter $A_{ep}$ is in good agreement with the theory that considers the incomplete drag of impurities by lattice vibrations. The spin-orbit scattering time extracted from the weak localization correction was found to be two orders of magnitude larger than the time given by the standard estimate $τ_{so}\approxτ\left(\hbar c/e^2Z\right)^4$. The theory of the EEI quantum correction was tested using the Hall coefficient and specific heat data for Ti-Si and $\left(Ag_{0.5}Cu_{0.5}\right)_{100-x}Ge_x$ amorphous alloys, which allowed us to estimate all microscopic parameters needed by the theory. We found that, within the accuracy of our measurements, the EEI theory works exactly for alloys that follow the free electron model [$\left(Ag_{0.5}Cu_{0.5}\right)_{100-x}Ge_x$ with $x\le50$.] The deviation from the theory observed in all Ti-Si alloys and in Ag-Cu-Ge alloys with $x\geq60$ can be qualitatively explained by weakening of the electron screening in the systems.
The $ν=5/2$ Fractional Quantum Hall State in the Presence of Alloy Disorder
我们报告的影响合金无序的$ν=5/2$分数量子霍尔态的定量测量。合金无序由量子阱的Al $_x$ Ga $_{1-x}$ As沟道中的铝含量$x$控制。我们发现合金散射抑制了$ν=5/2$态。令我们惊讶的是，在具有合金无序的样品中，当与其中合金无序不是主要散射机制的样品相比时，$ν=5/2$状态出现在显著降低的迁移率。我们的研究结果突出了不同类型的障碍存在于这些样品中，如短程合金和长程库仑无序的不同作用。
Giant Spin Hall Effect Induced by Skew Scattering from Bismuth Impurities inside Thin Film CuBi Alloys
我们证明了通过在Cu中引入少量Bi杂质可以诱导巨自旋霍尔效应（SHE）。基于一种新的三维自旋输运有限元方法的分析表明，Bi杂质诱导的SHE符号为负，其自旋霍尔角为-0.24。CuBi合金中的这种负的大SH角可以通过应用由Fert和Levy [Phys. Rev. Lett. 106，157208（2011）]至6p杂质。
Effects of Impurity Scattering on Orbital Hall Conductivity and Orbital Transport in Ru-based Alloys
State Key Laboratory of Semiconductor Physics and Chip Technologies, Institute of Semiconductors, Chinese Academy of Sciences（中国科学院半导体研究所半导体物理与芯片技术国家重点实验室）；College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences（中国科学院大学材料科学与光电技术学院）
Itinerant ferromagnetism and intrinsic anomalous Hall effect in amorphous iron-germanium
非晶铁-锗系统（$a$ Ge $_{1-x}$）缺乏长程结构有序性，因此缺乏有意义的布里渊区。\aFeGe的磁化强度由Stoner模型很好地解释，其中Fe浓度$x$高于$x=0.4$周围磁序的起始，表明非晶结构的局部序保留了$3d$态的自旋分裂态密度，足以使电子结构稳定，尽管$\mathbf{k}$是一个坏的量子数。测量揭示了增强的异常霍尔电阻率$ρ_{xy}^{\mathrm{AH}}$相对于结晶FeGe，这$ρ_{xy}^{\mathrm{AH}}$相比，密度泛函理论计算的异常霍尔电导率，以解决其潜在的机制。本征机制，通常理解为Berry曲率集成在占用$\mathbf{k}$ -状态，但在这里被证明是等效的曲率密度集成在非周期性材料中的占用能量，占主导地位的反常霍尔电导率的$a$ -Fe $_x$ Ge $_{1-x}$（$0.38 \leq x \leq 0.61$）。曲率密度是局部轨道态的自旋-轨道相关的总和，因此可以在不参考$\mathbf{k}$ -空间的情况下计算。这一结果和随之而来的Stoner-like模型的固有异常霍尔电导率建立了一个统一的理解的基础物理的异常霍尔效应在晶体和无序系统。
