Topological phase transition in nonchiral Rice-Mele model with bond disorder

TL;DR

This paper investigates how disorder affects topological phase transitions in the nonchiral Rice-Mele model, revealing disorder-induced transitions and anomalous localization phenomena using a symmetry-independent invariant.

Contribution

It introduces a novel analysis of disorder effects on topological phases in the Rice-Mele model using a global invariant independent of symmetry.

Findings

Disorder induces a topological phase transition in the model.

Anomalous localization occurs at a specific disorder strength, independent of mass.

Critical disorder strength decreases with increasing mass and stabilizes for large mass.

Abstract

The Rice-Mele model consists of a one-dimensional lattice with two sublattice sites in each unit cell subjected to a staggered sublattice potential. The onsite potential constitutes a mass term that breaks chiral symmetry. In this paper, we show that a topological phase transition is induced in this model by disordering intracell and intercell hopping energies unequally, by means of a symmetry-independent global invariant. For small enough mass, the phase transition is accompanied by anomalous localization, which is accounted for in terms of geometric means of random variables. The specific disorder strength at which anomalous localization occurs is independent of mass. In contrast, the critical disorder strength at which the phase transition takes place decreases as mass increases, and eventually becomes invariable for large enough mass. For large enough mass, we show that the phase transition is characterized by arithmetic means instead of geometric means.