Engineering of Chern insulators and circuits of topological edge states

TL;DR

This paper presents a robust method to create tunable Chern insulators by doping three-dimensional topological insulators with magnetic impurities, enabling control over topological states and edge channel circuits.

Contribution

It introduces a robust protocol for engineering Chern insulators from topological insulators using magnetic impurity doping, insensitive to impurity configuration.

Findings

Chern number can be tuned by one through impurity doping.

The method is robust against impurity arrangement.

Edge channel circuits can be engineered using this approach.

Abstract

Impurities embedded in electronic systems induce bound states which under certain circumstances can hybridize and lead to impurity bands. Doping of insulators with impurities has been identified as a promising route towards engineering electronic topological states of matter. In this paper we show how to realize tuneable Chern insulators starting from a three dimensional topological insulator whose surface is gapped and intentionally doped with magnetic impurities. The main advantage of the protocol is that it is robust, and in particular not very sensitive to the impurity configuration. We explicitly demonstrate this for a square lattice of impurities as well as a random lattice. In both cases we show that it is possible to change the Chern number of the system by one through manipulating its topological state. We also discuss how this can be used to engineer circuits of edge channels.