论文标题
二维拓扑绝缘子中的非磁性缺陷对螺旋边缘状态的远程扰动
Long-range perturbation of helical edge states by nonmagnetic defects in two-dimensional topological insulators
论文作者
论文摘要
我们研究由于轴向旋转对称性损坏的一般情况下，由于螺旋边缘状态（HESS）之间的隧道耦合（HESS）（HESS）和非磁点缺陷的结合状态而形成的电子状态。发现HESS和单个缺陷的耦合导致由结合状态和一组常规HESS组成的复合HES的形成。它们在缺陷附近的光谱密度相对于结合状态的能级移动。但最重要的是，缺陷周围的赫斯（Hess）的远程扰动，这是由传统边缘状态的两个kramers伙伴组成的云。因此，每个复合HESS都包含右和左移动的常规HESS。这种扰动的幅度随着与缺陷的距离而呈互为减少。在许多缺陷的系统中，这种扰动会导致由HESS介导的不同缺陷状态之间的远程耦合，并引起惊人的效果。我们研究了两个缺陷系统的这些效果，其中提出的间接耦合机理即使它们之间的距离非常大，也会导致隔离缺陷的共振分裂。结果，两峰共振的不对称结构会随着缺陷之间的距离而异常变化。
We study the electronic states that are formed due to the tunnel coupling between helical edge states (HESs) and bound states of nonmagnetic point defects in two-dimensional topological insulators in the general case of broken axial spin symmetry. It is found that the coupling of HESs and a single defect leads to the formation of composite HESs composed of the bound states and a set of the conventional HESs. Their spectral density near the defect has a resonance shifted relative to the energy level of the bound state. But of most importance is a long-range perturbation of the HESs around the defect, which is a cloud consisting of both Kramers partners of conventional edge states. Therefore each of the composite HESs contains both the right- and left-moving conventional HESs. The amplitude of this perturbation decreases inversely with the distance from the defect. In a system of many defects, this perturbation leads to a long-range coupling between bound states of different defects mediated by the HESs and causes amazing effects. We study these effects for a two-defect system where the proposed mechanism of indirect coupling leads to a splitting of the resonances of isolated defects even if the distance between them is very large. As a result an asymmetric structure of two-peak resonance arises that very unusually changes with the distance between the defects.
