Manipulation of valley splitting for the WSe<sub>2</sub>/NiCl<sub>2</sub> heterostructure by adjusting the interlayer spacing and constructing a NiCl<sub>2</sub>/WSe<sub>2</sub>/NiCl<sub>2</sub> heterojunction
Sukai Teng, Xiujuan Mao, Ze Liu, Yang Liu, Xiuting Xu, Linyang Li, Xinjian Xie, Shanshan Fan, Guoxiang Zhou, Jun Li, Jia Li
Abstract
Abstract The electronic band structure and valley splitting of the WSe 2 /NiCl 2 heterostructure have been investigated by density functional theory and Berry curvature calculations. We demonstrate that the valley polarization of monolayer WSe 2 is induced due to the magnetic proximity effect caused by the single layer of ferromagnetic NiCl 2 . The magnitude of valley splitting depends on the stacking configurations of WSe 2 /NiCl 2 , and the maximum value of valley splitting reaches −11.87 meV. Large valley splitting can be achieved by adjusting the layer spacing and constructing a NiCl 2 /WSe 2 /NiCl 2 heterojunction with Ni spins arranged in parallel between two NiCl 2 sheets. The valley-contrasting Berry curvature between the K and K ′ valleys suggests that the WSe 2 /NiCl 2 -based heterostructure could potentially be used as a valleytronic device to realize the valley-polarized anomalous Hall effect as both spin and valley filter.