Electronic states induced by nonmagnetic defects in two-dimensional topological insulators

Abstract

We study in-gap electronic states induced by a nonmagnetic defect with short-range potential in two-dimensional topological insulators and trace their evolution as the distance between the defect and the boundary changes. The defect located far from the boundary is found to produce two bound states independently of the sign of its potential. The states are classified as electronlike and holelike. Each of these states can have two types of the spatial distribution of the electron density. The first-type states have a maximum of the density in the center and the second-type ones have a minimum. When the defect is coupled with the boundary, the bound states are transformed correspondingly into resonances of two types and take up the form of the edge states flowing around the defect. Under certain conditions, two resonances interfere giving rise to the formation of a bound state embedded into the continuum spectrum of the edge states flowing around the defect. We calculate the spatial distribution of the electron density in the edge states flowing around the defect and estimate the charge accumulated near the defect. The current density field of the edge states flowing around the defect contains two components one of which flows around the defect and the other circulates around it.

arXiv comment11 pages, 7 figures

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• Effects of Defects and Dephasing on Charge and Spin Currents in Two-Dimensional Topological Insulators
• Electrically controlled crossing of energy levels in quantum dots in two-dimensional topological insulators
• Conductance suppression by nonmagnetic point defects in helical edge channels of two-dimensional topological insulators
• Singlet-triplet transition in double quantum dots in two-dimensional topological insulators
• Bound states and controllable currents on Topological Insulator surfaces with extended magnetic defects
• Optical transitions in two-dimensional topological insulators with point defects
• Long-range perturbation of helical edge states by nonmagnetic defects in two-dimensional topological insulators
• The Coulomb impurity in 2D materials with strong spin-orbit interaction
• Symmetry-protected topological wire in a topological vacuum
• Designing atomic-scale resistive circuits in topological insulators through vacancy-induced localized modes