Topological phenomena at topological defects

TL;DR

This paper reviews recent advances in understanding how topological defects interact with topological phases in materials, revealing new phenomena and potential applications in materials science.

Contribution

It provides a comprehensive survey of the emerging field exploring the interplay between topological defects and topological phases in materials.

Findings

Topological defects can induce novel topological phenomena in materials.

Experimental progress has revealed interactions between defects and topological states.

Potential applications include topological pumping and synthetic dimensions.

Abstract

There are two prominent applications of the mathematical concept of topology to the physics of materials: band topology, which classifies different topological insulators and semimetals, and topological defects that represent immutable deviations of a solid lattice from its ideal crystalline form. While these two classes of topological phenomena have generally been treated as separate topics, recent experimental advancements have begun to probe their intricate and surprising interactions, in real materials as well as synthetic metamaterials. Topological lattice defects in topological materials offer a platform to explore a diverse range of novel phenomena, such as topological pumping via topological defects, embedded topological phases, synthetic dimensions, and non-Hermitian skin effects. In this Perspective, we survey the developments in this rapidly moving field, and give an outlook of its impact on materials science and applications.