Multifunctional Two-dimensional van der Waals Janus Magnet Cr-based Dichalcogenide Halides

TL;DR

This study systematically investigates Cr-based Janus monolayer dichalcogenide halides, revealing their potential as high-temperature ferromagnetic semiconductors with multifunctional properties suitable for topological and valleytronic devices.

Contribution

First-principles analysis demonstrating the multifunctional magnetic, topological, and valleytronic properties of Cr-based Janus dichalcogenide halides.

Findings

CrSX monolayers are high TC ferromagnetic semiconductors.

Large-gap quantum anomalous Hall effect achieved via magnetic proximity.

Skyrmion states induced by Dzyaloshinskii-Moriya interactions.

Abstract

Two-dimensional van der Waals Janus materials and their heterostructures offer fertile platforms for designing fascinating functionalities. Here, by means of systematic first-principles studies on van der Waals Janus monolayer Cr-based dichalcogenide halides CrYX (Y=S, Se, Te; X=Cl, Br, I), we find that CrSX (X=Cl, Br, I) are the very desirable high TC ferromagnetic semiconductors with an out-of-plane magnetization. Excitingly, by the benefit of the large magnetic moments on ligand S2- anions, the sought-after large-gap quantum anomalous Hall effect and sizable valley splitting can be achieved through the magnetic proximity effect in van der Waals heterostructures CrSBr/Bi2Se3/CrSBr and MoTe2/CrSBr, respectively. Additionally, we show that large Dzyaloshinskii-Moriya interactions give rise to skyrmion states in CrTeX (X=Cl, Br, I) under external magnetic fields. Our work reveals that two-dimensional Janus magnet Cr-based dichalcogenide halides have appealing multifunctionalities in the applications of topological electronic and valleytronic devices.