Current-induced breakdown of the quantum anomalous Hall effect

TL;DR

This paper investigates the breakdown mechanism of the quantum anomalous Hall effect, identifying electric-field-driven percolation of charge puddles as the key cause, which limits device applications at high current densities.

Contribution

It introduces a new understanding of the breakdown mechanism in QAHE, highlighting the role of electric fields and charge puddle percolation in the dissipation loss.

Findings

Electric field between chiral edge states causes breakdown.

Percolation of charge puddles is the likely breakdown mechanism.

Breakdown occurs at relatively small critical currents.

Abstract

The quantum anomalous Hall effect (QAHE) realizes dissipationless longitudinal resistivity and quantized Hall resistance without the need of an external magnetic field. However, when reducing the device dimensions or increasing the current density, an abrupt breakdown of the dissipationless state occurs with a relatively small critical current, limiting the applications of the QAHE. We investigate the mechanism of this breakdown by studying multi-terminal devices and identified that the electric field created between opposing chiral edge states lies at the origin. We propose that electric-field-driven percolation of two-dimensional charge puddles in the gapped surface states of compensated topological-insulator films is the most likely cause of the breakdown.