Hexagon Ising-Kondo lattice: An implication for intrinsic antiferromagnetic topological insulator

TL;DR

This paper introduces an exactly solvable topological Ising-Kondo lattice model to understand the interplay of magnetism and topology in intrinsic antiferromagnetic topological insulators like MnBi$_2$Te$_4$, revealing rich phases and temperature effects.

Contribution

It proposes a novel analytical TIKL model capturing the physics of magnetic topological insulators and extends understanding of their phase diagram and thermal stability.

Findings

Rich topological and magnetic phases identified in the model.

Topological properties persist at high temperatures and can be restored.

The model provides insights for experimental tuning of magnetic topological states.

Abstract

Recently, the MnBi$_2$Te$_4$ material has been proposed as the first intrinsic antiferromagnetic topological insulator (AFMTI), where the interplay between magnetism and topology induces several fascinating topological phases, such as the quantum anomalous Hall effect, Majorana fermions, and axion electrodynamics. However, an exactly solvable model being capable to capture the essential physics of the interplay between magnetism and topology is still absent. Here, inspired by the the Ising-like nature [B. Li \textit{et al.} Phys. Rev. Lett. \textbf{124}, 167204 (2020)] and the topological property of MnBi$_2$Te$_4$, we propose a topological Ising-Kondo lattice (TIKL) model to study its ground state property in an analytical way at zero temperature. The resultant phase diagram includes rich topological and magnetic states, which emerge in the model proposed in a natural and consistent way for the intrinsic magnetic topological insulator. With Monte Carlo simulation, we extend the AFMTI ground state to finite temperature. It reveals that topological properties do sustain at high temperature, which even can be restored by elevated temperature at suitable correlation strength. The results demonstrate that TIKL may offer an insight for future experimental research, with which magnetism and transport properties could be fine tuned to achieve more stable and exotic magnetic topological quantum states.