High Chern number van der Waals magnetic topological multilayers MnBi$_2$Te$_4$/hBN

TL;DR

This paper proposes a theoretical method to realize high Chern number topological states in MnBi$_2$Te$_4$/hBN multilayers, enabling multiple chiral edge modes and higher quantized Hall conductance for advanced electronic applications.

Contribution

The study introduces a novel multilayer heterostructure design that achieves high Chern numbers, surpassing the typical C=1 limit in Chern insulators, using theoretical modeling.

Findings

High Chern number states with C=n are achievable in MnBi$_2$Te$_4$/hBN multilayers.

The high-C states exhibit n chiral edge modes.

Quantized Hall conductance of C e^2/h is realized both with and without external magnetic fields.

Abstract

Chern insulators are two-dimensional magnetic topological materials that conduct electricity along their edges via the one-dimensional chiral modes. The number of these modes is a topological invariant called the first Chern number $C$, that defines the quantized Hall conductance as $S_{xy}= C e^2/h$. Increasing $C$ is pivotal for the realization of low-power-consumption topological electronics, but there has been no clear-cut solution of this problem so far, with the majority of existing Chern insulators showing $C=1$. Here, by using state-of-the-art theoretical methods, we propose an efficient approach for the realization of the high-$C$ Chern insulator state in MnBi$_2$Te$_4$/hBN van der Waals multilayer heterostructures. We show that a stack of $n$ MnBi$_2$Te$_4$ films with $C=1$ intercalated by hBN monolayers gives rise to a high Chern number state with $C=n$, characterized by $n$ chiral edge modes. This state can be achieved both under the external magnetic field and without it, both cases leading to the quantized Hall conductance $S_{xy}= C e^2/h$. Our results therefore pave way to practical high-$C$ quantized Hall systems.