Designing Magnetic Topological van der Waals Heterostructure

TL;DR

This paper introduces a novel method for designing 2D magnetic topological heterostructures using van der Waals materials, enabling switchable topological states controlled by electric fields.

Contribution

It presents a new approach to create magnetic topological systems with coexisting magnetization and topology in the same layer, and demonstrates switchable topological phases via electric field in vdW heterostructures.

Findings

Realization of 2D topological systems with nonzero Chern number

Switchable topological states via electric field in trilayer structures

Coexistence of magnetization and topology in the same magnetic layer

Abstract

We demonstrate a new method of designing 2D functional magnetic topological heterostructure (HS) by exploiting the vdw heterostructure (vdw-HS) through combining 2D magnet CrI$_3$ and 2D materials (Ge/Sb) to realize new 2D topological system with nonzero Chern number (C=1) and chiral edge state. The nontrivial topology originates primarily from the CrI$_3$ layer while the non-magnetic element induces the charge transfer process and proximity enhanced spin-orbit coupling. Due to these unique properties, our topological magnetic vdw-HS overcomes the weak magnetization via proximity effect in previous designs since the magnetization and topology coexist in the same magnetic layer. Specifically, our systems of bilayer CrI$_3$/Sb and trilayer CrI$_3$/Sb/CrI$_3$ exhibit different topological ground state ranging from antiferromagnetic topological crystalline insulator (C$_M$= 2) to a QAHE. These nontrivial topological transition is shown to be switchable in a trilayer configuration due to the magnetic switching from antiferromagnetism to ferromangetism in the presence an external perpendicular electric field with value as small as 0.05 eV/A. Thus our study proposes a realistic system to design switchable magnetic topological device with electric field.