Effects of random domains on the zero Hall plateau in quantum anomalous Hall effect

TL;DR

This paper investigates how random domains influence the zero Hall plateau in quantum anomalous Hall insulators, revealing the role of symmetry and predicting a BKT-type transition affecting the critical behavior.

Contribution

It provides a theoretical analysis of the impact of random domains and symmetry on the zero Hall plateau transition in QAH systems, including a novel prediction of BKT-type transition.

Findings

Structure inversion symmetry affects the scaling of the zero Hall plateau.

Presence of symmetry leads to a quantum-Hall-type critical point.

Absence of symmetry results in a line of critical points and a BKT transition.

Abstract

Recently, a zero Hall conductance plateau with random domains is experimentally observed in quantum anomalous Hall (QAH) effect. We study the effects of random domains on the zero Hall plateau in QAH insulators. We find the structure inversion symmetry determines the scaling property of the zero Hall plateau transition in the QAH systems. In the presence of structure inversion symmetry, the zero Hall plateau state shows a quantum-Hall-type critical point, originating from the two decoupled subsystems with opposite Chern numbers. However, the absence of structure inversion symmetry leads to mixture between these two subsystems, gives rise to a line of critical points, and dramatically changes the scaling behavior. Hereinto, we predict a Berezinskii-Kosterlitz-Thouless-type transition during the Hall conductance plateau switching in the QAH insulators. Our results are instructive for both theoretic understanding of the zero Hall plateau transition and future transport experiments in the QAH insulators.