Charge-impurity-induced Majorana fermions in topological superconductors

TL;DR

This study numerically investigates how charged impurities can induce Majorana fermions in topological superconductors, revealing their localization and potential experimental detection methods.

Contribution

It demonstrates the formation and localization of Majorana fermions induced by charged impurities in both quasi-one-dimensional and two-dimensional topological superconductors, providing new insights.

Findings

Majorana fermions are localized at impurity sites in 1D systems.

In 2D systems, impurity-induced MFs resemble vortex-induced pairs.

Local density of states analysis suggests experimental detectability.

Abstract

We study numerically Majorana fermions (MFs) induced by a charged impurity in topological superconductors. It is revealed from the relevant Bogoliubov-de Gennes equations that (i) for quasi-one dimensional systems, a pair of MFs are bounded at the two sides of one charge impurity and well separated; and (ii) for a two dimensional square lattice, the charged-impurity-induced MFs are similar to the known pair of vortex-induced MFs, in which one MF is bounded by the impurity while the other appears at the boundary. Moreover, the corresponding local density of states is explored, demonstrating that the presence of MF states may be tested experimentally.