Topology-insensitive axion mass in magnetic topological insulators

TL;DR

This paper investigates the axion mass in magnetic topological insulators, revealing it remains stable across different magnetic states and topological phases, with implications for axion dark matter detection.

Contribution

It demonstrates that the axion mass in magnetic topological insulators is insensitive to topological phases and magnetic states, providing new insights for axion dark matter research.

Findings

Axion mass can reach up to eV scale in magnetic topological insulators.

Axion mass approaches zero near magnetic phase boundaries.

The axion mass is insensitive to the topological state of the insulator.

Abstract

We study the axion in three-dimensional topological insulators with magnetic impurities under finite temperature. We find a stable antiferromagnetic ground state and ferromagnetic metastable state. In both magnetic states, the mass of the axion is found to be up to eV scale and it approaches zero near the phase boundary of the magnetic state. This result applies to both normal and topological insulator phases, i.e., the axion mass is insensitive to the topological states, and it will have a direct impact on the targeted mass range of particle axion dark matter in future experiments.