Oscillated Dzyaloshinskii-Moriya interaction at hydrogenated Graphene/Co interfaces

Magnetic topological structures such as chiral domain walls and Skyrmions are becoming a hot topic due to its potential application for future information storage. One of the key ingredient for the formation of these spintextures is the Dzyaloshinskii-Moriya interaction (DMI) in symmetry broken systems. Recently, it was reported that DMI can be induced in Co/Gr heterostructure due to the Rashba effect.[1] Considered that hydrogenated graphene (H-graphene) can enhance the spin orbit coupling of carbon atoms. Therefore, here, we propose to use interfaces between Co and H-graphene to tune DMI. Using first principles calculations, we find that the strength of DMI can be largely modulated by the concentration of H coverage on graphene, e.g., the anti-clockwise chiral of Co/Gr could be tuned to clockwise chiral in a Co(2ML)/1/2H-graphene with amplitude up to 1.0 meV/bond. Moreover, there is an obvious oscillation of DMI as a function of Co thickness ranging from 1ML to 7ML. The strength of DMI and this oscillation may origin from the change of SOC energy and electron filling in Co/Gr with different hydrogen concentration.

[1] Hongxin Yang, et al. Nat. Mater. 17, 605 (2018).