Reversible control of Dzyaloshinskii-Moriya interaction at graphene/Co interface via hydrogen absorption

TL;DR

This study demonstrates that hydrogenation at the graphene/Co interface can reversibly modulate the magnitude and chirality of the Dzyaloshinskii-Moriya interaction, offering a new method for spintronic control.

Contribution

It reveals how hydrogen absorption influences DMI at the graphene/Co interface and uncovers the underlying electronic mechanisms involved.

Findings

Hydrogenation controls DMI magnitude and chirality.

DMI oscillates with Co thickness in a two-atomic-layer period.

Spin splitting and Co-d orbital occupation are key factors.

Abstract

Using first-principles calculations, we investigate the impact of hydrogenation on the Dzyaloshinskii-Moriya interaction (DMI) at graphene/Co interface. We find that both the magnitude and chirality of DMI can be controlled via hydrogenation absorbed on graphene surface. Our analysis using density of states combined with first-order perturbation theory reveals that the spin splitting and the occupation of Co-d orbitals, especially the dxz and dz2 states, play a crucial role in defining the magnitude and the chirality of DMI. Moreover, we find that the DMI oscillates with a period of two atomic layers as a function of Co thickness what could be explained by analysis of out-of-plane of Co orbitals. Our work elucidates the underlying mechanisms of interfacial DMI origin and provides an alternative route of its control for spintronic applications.