We study theoretically the effective spin Hall properties of a composite consisting of two materials with and without spin-orbit (SO) coupling. In particular, we assume that SO material represents a system of grains in a matrix with no SO. We calculate the effective spin Hall angle and the effective spin diffusion length of the mixture. Our main qualitative finding is that, when the bare spin diffusion length is much smaller than the radius of the grain, the effective spin diffusion length is strongly enhanced, well beyond the "geometrical" factor. The physical origin of this additional enhancement is that, with small diffusion length, the spin current mostly flows around the grain without suffering much loss. We also demonstrate that the voltage, created by a spin current, is sensitive to a very weak magnetic field directed along the spin current, and even reverses sign in a certain domain of fields. The origin of this sensitivity is that the spin precession, caused by magnetic field, takes place outside the grains where SO is absent.
Tailoring Hybrid Anomalous Hall Response in Engineered Magnetic Topological Insulator Heterostructures
在新兴的磁性拓扑绝缘体（MTIs）中设计反常霍尔效应（AHE）在量子信息处理和自旋电子学应用中具有巨大的潜力。在这封信中，我们合成的外延Bi 2 Te 3/MnTe磁性异质结，并观察到明显的AHE信号从两个层结合在一起。所得到的混合AHE强度与顶部Bi 2 Te 3层厚度的演变表明在异质层界面处的拓扑表面态诱导的本征铁磁相的存在。更重要的是，通过用Sb掺杂Bi 2 Te 3层，我们能够操纵Berry相关联的AHE分量的符号。我们的研究结果表明，MTI异质结构的非线性优势，磁掺杂的TI对应物，其中AHE响应的可调谐性可以大大提高。这反过来又为基于MTI异质结构的多功能应用开辟了新的途径。
Tailoring pure valley-Zeeman spin-orbit coupling in WSe$_2$-encapsulated monolayer graphene
National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University（南京大学固体微结构物理国家重点实验室、先进微结构协同创新中心、物理学院）；Center for Quantum Matter, School of Physics, Zhejiang University（浙江大学量子物质科学研究中心、物理学院）
Tailoring the properties of YBa$_{2}$Cu$_{3}$O$_{7-δ}$ thin films by 30-keV He$^+$ irradiation: An enabling route to superconducting device nanopatterning
University of Vienna（维也纳大学）；Universität Tübingen, Physikalisches Institut, Center for Quantum Science (CQ) and LISA +（蒂宾根大学物理学院，量子科学中心（CQ）和LISA+）
Topological Phase Transitions Induced by Disorder in Magnetically Doped (Bi, Sb)$_2$Te$_3$ Thin Films
利用大尺度输运模拟方法研究了磁掺杂（Bi，Sb）$_2$ Te $_3$薄膜中无序诱导的拓扑相变.在未掺杂和清洁的情况下，富相图除了与无序强度有关外，还与磁交换场、费米能级和初始拓扑状态密切相关。在非零交换场的初始平凡系统中，改变无序强度可以诱导从正常绝缘态到量子反常Hall态，然后是自旋-陈氏绝缘态，最后是安德森绝缘态的一系列跃迁。而对于最初具有拓扑结构的系统，可以诱导出类似的序列，但只能从量子反常霍尔态开始。通过改变费米能级，我们发现了一个类似的丰富的相图，包括从量子反常霍尔到自旋-陈绝缘态的跃迁，通过一个表现为量子反常霍尔和金属态的混合物的状态，类似于最近的实验报告。
Field-Free Reconfigurable Spin Logic in Compositionally Graded MnxCoAl Layer
Institute of Semiconductors, Chinese Academy of Sciences（中国科学院半导体研究所）；University of Chinese Academy of Sciences（中国科学院大学）；Hangzhou International Innovation Institute, Beihang University（北京航空航天大学杭州创新研究院）；Institut Jean Lamour, Université de Lorraine, CNRS（洛林大学让·拉穆尔研究所）
