Spin-Charge Locked Magneto-Transport and Mesoscopic Interference Phenomenain Topological Insulators

真正的介观干涉效应在拓扑绝缘体中获得增加的复杂性，其中相干电子传导是基于拓扑上非平凡的螺旋表面状态包裹在名义上绝缘的体上。我们计划在介观尺度上系统地研究磁输运通过弹道和无序拓扑绝缘体的各个方面和现象，特别关注量子相干性和拓扑之间的相互作用。为此，将考虑以下相互关联的目标：(i)从第一个资助期开始扩展我们有前途的研究，我们将解决二维结构中量子自旋霍尔边缘电导率的限制和鲁棒性，重点是由于长期潜在波动引起的电荷坑的作用。（ii）我们将考虑三维拓扑绝缘体纳米线及其结构的磁导率中的量子干涉效应，特别是aharonov - bohm型特征。（iii）我们将研究三维拓扑绝缘体纳米结构表面的耦合电荷和自旋动力学，重点研究多端构型的非局部效应和门控的作用。特别是，鉴于自旋动量锁定，我们将探讨通过铁磁接触注入/提取自旋的后果。一方面，我们将采用介观导体理论的解析技术，另一方面，考虑无序、自旋轨道相互作用和静电门控效应，对基于hgte的拓扑绝缘体的实际模型进行有效的数值紧密结合输运编码。我们的研究将与相应的二维和三维拓扑绝缘体的量子输运实验密切合作。

Genuine mesoscopic interference effects acquire increased complexity in topological insulators, where coherent electronic conduction is based on topologically non-trivial helical surface states wrapping around a nominally insulating bulk. We plan to systematically investigate various aspects and phenomena of magneto-transport through ballistic and disordered topological insulators at mesoscopic scales with particular focus on the interplay between quantum coherence and topology. To this end will consider the following inter-related objectives: (i) Extending our promising studies from the first funding period we will address the limits and robustness of quantum spin Hall edge conductance in 2D structures with emphasis on the role of charge puddles due to long-range potential fluctuations. (ii) We will consider quantum interference effects, in particular Aharonov-Bohm-type features, in the magneto-conductance of 3D topological insulator nanowires and structures built from them. (iii) We will investigate the coupled charge and spin dynamics on the surface of 3D topological insulator nanostructures, with emphasis on non-local effects in multi-terminal configurations and the role of gating. In particular, we will explore, in view of spin-momentum locking, the consequences of spin injection/extraction via ferromagnetic contacts.On the one hand we will employ analytical techniques from the theory of mesoscopic conductors and on the other hand efficient numerical tight-binding transport codes for realistic models of HgTe-based topological insulators by taking into account disorder, spin-orbit interaction and electrostatic gating effects. We will perform our investigations in close cooperation with corresponding experiments on quantum transport in 2D and 3D topological insulators.