Topological Anderson insulators by latent symmetry

TL;DR

This paper introduces a method to identify and design topological Anderson insulators protected by hidden, latent symmetries revealed through isospectral reduction, expanding understanding of disorder-induced topological phases.

Contribution

It proposes a novel approach to uncover and engineer topological Anderson insulators using latent symmetries revealed by isospectral reduction techniques.

Findings

Design of disordered chains with latent symmetries

Identification of topological states via invariants and localization length

Extension of topological classification to latent symmetry cases

Abstract

Topological Anderson insulators represent a class of disorder-induced, nontrivial topological states of matter. In this study, we propose a feasible strategy to unveil and design topological Anderson insulators protected by latent symmetries. These are not visible in the original system, but become obvious after performing an isospectral reduction. Using this technique, we design a family of disordered multi-atomic chains that exhibit latent chiral symmetry or mirror (inversion) symmetry. Using topological invariants, bulk polarization, and the divergence of localization length of the topological bound edge states in the reduced disordered system, we show how to identify the gapped and ungapped topological Anderson states in the original systems. Our work thus extends the concept of topological Anderson insulating phases protected by geometric symmetries and tenfold-way classification to the various types of latent symmetry cases. Overall, our work paves the way for exploiting topological Anderson insulators in terms of latent symmetries.