Valleytronics Candidate with Spontaneous Valley Polarization in A-Type Antiferromagnetic MoSi<sub>2</sub>N<sub>4</sub>/MnPS<sub>3</sub> Heterostructure
Xiao-Jing Dong, Jia Kang, Wei-xiao Ji, Shengshi Li, Changwen Zhang
Abstract
Two-dimensional (2D) antiferromagnetic (AFM) heterostructures (HTSs) have broad application prospects since they offer a stray-free field, robustness against magnetic perturbations, and faster spin dynamics, but how to effectively control valley polarization with an AFM substrate is still an issue. Here spin–valley physical coupling in monolayers of MoSi 2 N 4 and AFM MnPS 3 is due to spin–orbit coupling and the absence of inversion symmetry, which made broad application prospects of spin and valley in novel 2D materials. Spontaneous valley polarization in MoSi 2 N 4 /MnPS 3 HTS has been confirmed by using the first-principles calculations and low-energy effective Hamiltonian models. We reveal that its Néel temperature calculated by Monte Carlo simulation is about 340 K above room temperature, which is higher than many 2D AFM materials. The magnetic proximity phenomenon caused by interfacial orbital hybridization is gradually strengthened thanks to the reduction of the distance between the two layers, and valley splitting of the MoSi 2 N 4 /MnPS 3 HTS is calculated to be Δ K – K ′ = 9.15 meV. Our computational results offer a basis for the valley polarization in an intrinsic AFM HTS and a practical approach to design and utilize valleytronics devices.