Strain-Tailored Magnetic Anisotropy and Dzyaloshinskii-Moriya Interaction at MoS2/Fe4N(111) Interface

Abstract

Topological chiral spin textures, such as chiral domain walls and magnetic skyrmions, offer a unique opportunity to bring topology into room-temperature spintronic devices [1]. The stability of chiral spin textures is defined by the competition of Heisenberg exchange coupling, magnetic anisotropy and interfacial Dzyaloshinskii-Moriya interaction (DMI) [2], which can be engineered by the customized magnetic interfaces. Fe4N has been considered as a promising material in spintronic devices thanks to the high saturation magnetization, high Curie temperature and high spin polarization [3]. However, low magnetocrystalline anisotropy seriously prevents it from being an ideal candidate for magnetic information storage. The traditional approach for perpendicular magnetic anisotropy (PMA) and interfacial DMI engineering is to use ferromagnet (FM)/oxide interfaces [4], multilayer structures comprising FM/nonmagnetic metal (NM) interfaces [5], or graphene/FM interfaces [6]. Recent theoretical prediction and experimental evidence have triggered interest in the hybrid interfaces between 3d FMs and two-dimensional transition-metal dichalcogenides (2D TMDs) [7,8]. The potentials of 2D TMDs in pushing magnetic information storage to the atomic thin limit, the ability to form hybrid interfaces without the need for lattice matching, as well as the attractive semiconducting electronic band structures, provide advantages for magnetization manipulation at atomic-scale interfaces. For 2D TMDs, The lack of inversion center in the crystal structure provides significant advantage, which is already used to obtain unconventional PMA at 2D TMDs/FM interfaces. In addition, 2D TMDs are very promising to enhance the DMI parameter at 2D TMDs/FM interfaces owing to their intrinsic spin-orbit coupling (SOC). In this work, the magnetic anisotropy and DMI of MoS2/Fe4N(111) interfaces are investigated via first-principles calculations. It is found that the large PMA and anticlockwise chiral DMI appear at the MoS2/Fe4N(111) interface. Strong variations of the PMA and DMI parameters are demonstrated by applying in-plane biaxial strain of the interfaces. The variations of PMA and DMI under strain can be attributed to the hybridization of in-plane and out-of-plane d orbitals in interfacial Fe atom layer, respectively. These results show the possibility of stabilizing chiral spin textures in the 2D TMDs/FM systems. Further, the method of strain controlling PMA and DMI at MoS2/Fe4N interface opens another pathway for the development of spintronic devices using 2D TMDs.This work is supported by National Natural Science Foundation of China (51871161 and 52071233). **