High Chern number van der Waals magnetic topological multilayers MnBi2Te4/hBN

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 Sxy = Ce2/h. Increasing C is pivotal for the realization of low-power-consumption topological electronics, but there has been no clear-cut solution to 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 state in MnBi2Te4/hBN van der Waals multilayer heterostructures. We show that a stack of n MnBi2Te4 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 Sxy = Ce2/h. Our results, therefore, pave the way to practical high-C quantized Hall systems.