Anomalous valley Hall effect in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>A</mml:mi></mml:math>-type antiferromagnetic van der Waals heterostructures
Yingmei Zhu, Qirui Cui, Yonglong Ga, Jinghua Liang, Hongxin Yang
Abstract
Besides the charge and spin of electrons, the valley index is considered as another degree of freedom, which can be used as an information carrier in advanced electronic devices. The key for realizing applications of valleytronic devices is inducing and regulating valley polarization. Ferrovalley materials have ferromagnetism and valley features and exhibit interesting properties, e.g., anomalous valley Hall effect (AVHE). Also, the valley properties can be tuned efficiently by an electric field. Here, using first-principles calculations, we find that the $A$-type antiferromagnetic (AFM) $\mathrm{V}{\mathrm{Se}}_{2}/\mathrm{Cr}{\mathrm{I}}_{3}$ heterostructure (HS) can realize perpendicular magnetic anisotropy and spontaneous valley polarization for realizing AVHE, while the magnetic anisotropy of ${\mathrm{VSe}}_{2}$ is in plane. Furthermore, we build a multiferroic HS ${\mathrm{In}}_{2}{\mathrm{Se}}_{3}/\mathrm{V}{\mathrm{Se}}_{2}/\mathrm{Cr}{\mathrm{I}}_{3}$ by capping a ferroelectric (FE) layer (${\mathrm{In}}_{2}{\mathrm{Se}}_{3}$) on the $\mathrm{V}{\mathrm{Se}}_{2}/\mathrm{Cr}{\mathrm{I}}_{3}$ HS, to realize electric-field-controlled valley states. The half metal-to-semiconductor transition is achieved by switching the FE polarization from down to up, which is accompanied by turning off and on valley properties in this multiferroic HS. Our finding provides an alternative way for achieving and modulating spontaneous valley polarization and will be useful for spintronic and valleytronic devices based on the two-dimensional $A$-type AFM van der Waals HS.