论文标题
量子旋转厅边缘的电导率从第一原理：磁杂质和边缘间散射的关键作用
Conductance of quantum spin Hall edge states from first principles: the critical role of magnetic impurities and inter-edge scattering
论文作者
论文摘要
事实证明，在二维时段不变的拓扑绝缘子的边缘预期的出色运输属性已经具有挑战性，可以在实验中实现，并且到目前为止仅在非常短的设备中得到证明。为了寻求对这种令人困惑的观察的解释，我们在这里报告了基于非平衡绿色的功能形式的新型量子旋转厅绝缘子边缘的拓扑保护运输的完整第一原理计算。我们的计算揭示了可能影响二维拓扑绝缘子的两种不同的散射机制，即在空缺缺陷处发生时间反转对称性，并由多个合作的杂质（可能是非磁性）介导的介导的间边缘散射。我们讨论了它们对典型的非本地运输测量结果的巨大后果，以及减轻其负面影响的策略。最后，我们将拓扑保护的边缘状态与MOS $ _2 $丝带中的琐碎边缘状态的运输特性提供了一种有益的比较。尽管我们专注于一些特定情况（就材料和缺陷类型而言），但我们的结果应该代表一般情况，因此在此处研究的系统之外具有重要意义。
The outstanding transport properties expected at the edge of two-dimensional time-reversal invariant topological insulators have proven to be challenging to realize experimentally, and have so far only been demonstrated in very short devices. In search for an explanation to this puzzling observation, we here report a full first-principles calculation of topologically protected transport at the edge of novel quantum spin Hall insulators - specifically, Bismuth and Antimony halides - based on the non-equilibrium Green's functions formalism. Our calculations unravel two different scattering mechanisms that may affect two-dimensional topological insulators, namely time-reversal symmetry breaking at vacancy defects and inter-edge scattering mediated by multiple co-operating impurities, possibly non-magnetic. We discuss their drastic consequences for typical non-local transport measurements as well as strategies to mitigate their negative impact. Finally, we provide an instructive comparison of the transport properties of topologically protected edge states to those of the trivial edge states in MoS$_2$ ribbons. Although we focus on a few specific cases (in terms of materials and defect types) our results should be representative for the general case and thus have significance beyond the systems studied here.
