Realization of Semiconducting Layered Multiferroic Heterojunctions via Asymmetrical Magnetoelectric Coupling

TL;DR

This paper presents a novel approach to creating 2D semiconducting multiferroics by engineering van der Waals heterojunctions, demonstrating switchable magnetoelectric coupling and multiferroicity in a CrI3/In2Se3 heterostructure.

Contribution

It introduces a general mechanism for realizing semiconducting 2D multiferroics through heterojunction engineering, highlighting switchable orbital coupling and magnetoelectric effects.

Findings

Switchable indirect orbital coupling between Se 4p and Cr 3d orbitals.

Strong asymmetrical magnetoelectric coupling observed.

Potential to design tunable 2D multiferroics with various layer thicknesses.

Abstract

Two-dimensional (2D) semiconducting multiferroics that can effectively couple magnetic and polarization (P) orders have great interest for both fundamental research and technological applications in nanoscale, which are, however, rare in nature. In this study, we propose a general mechanism to realize semiconducting 2D multiferroics via vdW heterojunction engineering, as demonstrated in a typical heterostructure consisting of magnetic bilayer CrI3 (bi-CrI3) and ferroelectric monolayer In2Se3. Interestingly, the novel indirect orbital coupling between Se 4p and Cr 3d orbitals, intermediated by the interfacial I 5p orbitals, are switchable in the opposite P configurations, resulting in an unexpected mechanism of strong asymmetrical magnetoelectric coupling. Therefore, along with the noticeable ferroelectric energy barrier induced by In2Se3, the realization of opposite magnetic orders in opposite P configurations can eventually result in the novel multiferroicity in bi-CrI3/In2Se3. Finally, we demonstrate that our mechanism can generally be applied to design other vdW multiferroics even with tunable layer thickness.