Rashba-Type Dzyaloshinskii-Moriya Interaction, Perpendicular Magnetic Anisotropy, and Skyrmion States at 2D Materials/Co Interfaces.

ABSTRACT

We report a significant Dzyaloshinskii-Moriya interaction (DMI) and perpendicular magnetic anisotropy (PMA) at interfaces comprising hexagonal boron nitride (h-BN) and Co. By comparing the behavior of these phenomena at graphene/Co and h-BN/Co interfaces, it is found that the DMI in the latter increases as a function of Co thickness and beyond three monolayers stabilizes with 1 order of magnitude larger values compared to those at graphene/Co, where the DMI shows opposite decreasing behavior. Meanwhile, the PMA for both systems shows similar trends with larger values for graphene/Co and no significant variations for all thickness ranges of Co. Furthermore, using micromagnetic simulations we demonstrate that such significant DMI and PMA values remaining stable over a large range of Co thickness give rise to the formation of skyrmions with small applied external fields. These findings open up further possibilities toward integrating two-dimensional (2D) materials in spin-orbitronics devices.