Localization at the Edge of 2D Topological Insulator by Kondo Impurities with Random Anisotropies

TL;DR

This paper demonstrates that even weak anisotropic disorder in Kondo impurity couplings causes Anderson localization of edge states in 2D topological insulators, using a mapping to charge density wave pinning.

Contribution

It introduces a novel mapping of disordered Kondo impurity interactions to charge density wave pinning, revealing localization effects in topological insulator edges.

Findings

Weak anisotropic disorder induces Anderson localization of edge states.

Mapping to charge density wave pinning explains localization mechanism.

Localization occurs for arbitrarily small disorder strengths.

Abstract

We consider chiral electrons moving along the 1D helical edge of a 2D topological insulator and interacting with a disordered chain of Kondo impurities. Assuming the electron-spin couplings of random anisotropies, we map this system to the problem of the pinning of the charge density wave by the disordered potential. This mapping proves that arbitrary weak anisotropic disorder in coupling of chiral electrons with spin impurities leads to the Anderson localization of the edge states.