Thermal and thermoelectric properties of an antiferromagnetic topological insulator MnBi$_2$Te$_4$

TL;DR

This study investigates the thermal and thermoelectric properties of the antiferromagnetic topological insulator MnBi$_2$Te$_4$, revealing strong coupling between charge, lattice, and spin, and a significant anomalous Nernst effect linked to Berry curvature.

Contribution

It provides the first comprehensive analysis of thermal and thermoelectric transport in MnBi$_2$Te$_4$, highlighting the interplay of magnetic, electronic, and thermal properties in this topological insulator.

Findings

Strong coupling between charge, lattice, and spin degrees of freedom.

Observation of a large anomalous Nernst signal.

Temperature and magnetic field dependence of transport properties.

Abstract

The discovery of an intrinsic antiferromagnetic topological insulator (AFM-TI) in MnBi$_2$Te$_4$ has attracted intense attention, most of which lies on its electrical properties. In this paper, we report electronic, thermal, and thermoelectric transport studies of this newly found AFM-TI. The temperature and magnetic field dependence of its resistivity, thermal conductivity, and Seebeck coefficient indicate strong coupling between charge, lattice, and spin degrees of freedom in this system. Furthermore, MnBi$_2$Te$_4$ exhibits a large anomalous Nernst signal, which is associated with non-zero Berry curvature of the field-induced canted antiferromagnetic state.