The translational side of topological band insulators

TL;DR

This paper explores the less-studied bulk properties of topological band insulators, emphasizing the role of lattice defects like dislocations and their connection to the topological characteristics of the material.

Contribution

It provides a perspective on the impact of lattice defects, especially dislocations, on the topological nature of the bulk in topological insulators, an area less explored compared to edge states.

Findings

Dislocations can host topologically protected states.

Bulk properties influenced by lattice defects are crucial for understanding topological phases.

The study highlights the importance of defects in the topological behavior of materials.

Abstract

Spin-orbit coupled materials have attracted revived prominent research interest as of late, especially due their direct connection with topological notions. Arguably, a hallmark of this pursuit is formed by the concept of the topological band insulator (TBI). In these incompressible systems band inversions, often driven by strong spin-orbit coupling, result in a state that is topologically distinct from the usual insulator as long as time reversal symmetry is maintained. More generally, topological states that arise by virtue of a protecting symmetry have resulted in a flourishing research field on both the experimental as well as theoretical side of the condensed matter agenda. As a prime signature topological band insulators can exhibit protected spin filtered edge states, whose time reversal invariant partner is spatially separated on the other edge. While these edge states have resultantly been identified with many exotic physical phenomena, we here wish to provide a perspective on the equally rich, although far less explored, aspects of the bulk. That is, we will focus on the role of lattice defects, dislocations in particular, and their relation with the topological nature of the bulk.