Electrically tunable anomalous Hall conductivity in ferrovalley–ferroelectric heterostructure VSe2/Sc2CO2

Abstract

Electrical control of anomalous Hall conductivity (AHC) and valley polarisation are necessary to realize energy-efficient devices for information storage that exploit the valley degrees of freedom in a material. Robustness in electrical control is easily realizable in ferroelectric materials having bistable electric polarisations, while manipulation of valley properties is possible in ferrovalley materials. Combining two such materials would make a valleytronics device that is electrically controllable. In this work, we investigate the possibility of the electric field-induced switching of the AHC and spin–orbit coupling-induced valley polarization in the two-dimensional (2D) ferrovalley/ferroelectric VSe₂/Sc₂CO₂ heterostructure. We find that the valley degeneracy in this system is lifted by intrinsic spin–orbit coupling, leading to a substantial valley polarization and AHC. Upon application of an electric field, valley polarisation is significantly modified along with a sign reversal of AHC when the direction of the electric field is reversed. Modifications in the band structure leading to changes in the valley occupancy under the influence of an electric field are responsible for these. Our finding suggests that electric field-induced AHC switching is possible in this 2D heterostructure without the introduction of dopants or defects.