The Magnetic Proximity Effect Induced Large Valley Splitting in 2D InSe/FeI2 Heterostructures

Abstract

The manipulation of valley splitting has potential applications in valleytronics, which lacks in pristine two-dimensional (2D) InSe. Here, we demonstrate that valley physics in InSe can be activated via the magnetic proximity effect exerted by ferromagnetic FeI2 substrate with spin-orbit coupling. The valley splitting energy can reach 48 meV, corresponding to a magnetic exchange field of ~800 T. The system also presents magnetic anisotropy behavior with its easy magnetization axis tunable from in-plane to out-of-plane by the stacking configurations and biaxial tensile strain. The d-orbital-resolved magnetic anisotropic energy contributions indicate that the tensile strain effect arises from the increase of hybridization between minority Fe dxy and dx2−y2 states. Our results reveal that the magnetic proximity effect is an effective approach to stimulate the valley properties in InSe to extend its spintronic applications, which is expected to be feasible in other group-III monochalcogenides.

Recent advances in two-dimensional intrinsic ferromagnetic materials Fe3X(X=Ge and Ga)Te2 and their heterostructures for spintronics

“…Valley information has emerged as an information carrier to store, process and compile information, which has the advantages of high-speed and low-power consumption 173 with respect to charge carriers in traditional semiconductor technology. 174 The manipulation of the degrees of valley freedom has been demonstrated, and a field called valley electronics, or valleytronics, is springing up. As a star family of 2D materials, most transition metal chalcogenides (TMCs) exhibit degenerate valleys owing to the protection of time-reversal symmetry, which is unsuitable for information storage.…”

Spontaneous and tunable valley polarization in two-dimensional single-layer LaCl2

“…Breaking the time inversion symmetry by introducing magnetic exchange field can generate valley polarization. The usual methods for introducing magnetic exchange fields include magnetic proximity effect [29][30][31][32][33][34][35][36][37][38][39][40], magnetic atom doping [41][42][43][44][45][46][47], and applying external magnetic field [48][49][50][51]. When the time reversal symmetry is broken and the spin-orbit coupling (SOC) is considered, valley splitting will occur at the high symmetric points K and K ′ , leading to valley polarization.…”

First-Principles Studies of the Tunneling Properties through Ferroelectric/Ferromagnetic van der Waals Heterostructures

“…It has been reported that vdWHs could exhibit various interesting electronic, − optical, , and magnetic , features. Furthermore, they can be effectively modulated by electrical, mechanical, , and optical , means. The multifunctionality and high tunability of vdWHs increase the applicability of 2D materials in nanodevices, for example, photodetectors, − transistors, , and spintronic devices. ,, …”