Impurity-induced states on the surface of 3D topological insulators

TL;DR

This paper investigates how local impurities affect the electronic and spin structures on the surface of 3D topological insulators, revealing impurity-induced resonance states and anisotropic magnetic interactions.

Contribution

It provides detailed calculations of impurity effects on the local density of states and spin textures, highlighting the resilience of the Dirac point and the nature of magnetic coupling.

Findings

Impurities create low-energy resonance states near the Dirac point.

The Dirac point remains intact despite local disruptions.

Magnetic impurities induce anisotropic RKKY interactions.

Abstract

We calculate the modification of the local electronic structure caused by a local impurity on the surface of a 3D Topological Insulator. We find that the LDOS around the Dirac point of the electronic spectrum at the surface is significantly disrupted near the impurity by the creation of low-energy resonance state(s) -- however, this is not sufficient to (locally) destroy the Dirac point. We also calculate the non-trivial spin textures created near the magnetic impurities and discover anisotropic RKKY coupling between them.