Breakdown of the quantum anomalous Hall effect under microwave drives

TL;DR

This paper investigates how microwave irradiation causes breakdown of the quantum anomalous Hall effect in V-doped (Bi,Sb)$_2$Te$_3$ films, revealing heating effects that impair zero-resistance states and informing GHz-range applications.

Contribution

It provides a detailed characterization of microwave-induced breakdown in QAH insulators, highlighting the role of electron-hole puddle heating and hopping transport mechanisms.

Findings

Microwave fields increase longitudinal resistance in QAH devices.

Heating of electron-hole puddles under microwave irradiation promotes hopping transport.

Insights into GHz-range QAH device performance and limitations.

Abstract

Quantum anomalous Hall (QAH) insulators exhibit chiral dissipationless edge states without an external magnetic field, making them a promising material for quantum metrology and microwave applications. However, the breakdown of the zero-resistance state at low currents hinders progress. We investigate and characterize this breakdown under microwave fields (1-25 GHz) by measuring the increase of longitudinal resistance in RF Hall bars and RF Corbino devices made from V-doped (Bi,Sb)$_2$Te$_3$ films. Our results point to the role of heating of electron-hole puddles under microwave irradiation, thereby fostering hopping transport. Our work offers insights critical for GHz-range QAH applications.