Anti-commutative dynamical magneto-electric response in certain solid state materials

TL;DR

This paper introduces a new anti-commutative dynamical magneto-electric response in certain materials, which is gauge-independent, non-quantized, and observable in antiferromagnetic compounds like Mn₂Bi₂Te₅, expanding understanding of topological magneto-electric effects.

Contribution

It identifies a novel anti-commutative magneto-electric response term that differs from the axion field response, and proposes Mn₂Bi₂Te₅ as a candidate material to observe this effect.

Findings

Discovered a new gauge-independent, non-quantized magneto-electric response term.

Proposed Mn₂Bi₂Te₅ as a candidate material for observing dynamical magneto-electric currents.

Linked the large response to band inversion in the material.

Abstract

Axion field induced topological magneto-electric response has attracted lots of attentions since it was first proposed by Qi et al. in 2008. Here we find a new type of anti-commutative magneto-electric response \beta^{\xi}(\omega), which can induce a dynamical magneto-electric current driven by a time-varying magnetic field. Unlike the Chern-Simons Axion term, this magneto-electric response term is gauge-independent and non-quantized, and manifests in the systems breaking the symmetries of the time-reversal, inversion and mirror. In particular, we propose the antiferromagnetic material Mn_{2}Bi_{2}Te_{5} as a material candidate to observe dynamical magneto-electric current, in which a large magneto-electric response term \beta^{\xi}(\omega) originates from band inversion.