Zero-field spin resonance in graphene with proximity-induced spin-orbit coupling

TL;DR

This paper explores zero-field collective spin excitations in graphene with proximity-induced Rashba and valley-Zeeman spin-orbit coupling, revealing detectable ESR and EDSR modes and how electron interactions influence their spectral features.

Contribution

It demonstrates the existence of zero-field collective spin modes in graphene with SOC and shows how electron interactions affect their resonance spectra, enabling extraction of SOC and interaction parameters.

Findings

Detection of zero-field ESR and EDSR modes in graphene with SOC

Electron-electron interactions split resonance peaks

Resonance features can reveal SOC and many-body parameters

Abstract

We investigate collective spin excitations in graphene with proximity-induced spin-orbit coupling (SOC) of the Rashba and valley-Zeeman types, as it is the case, e.g., for graphene on transition- metal-dichalcogenide substrates. It is shown that, even in the absence of an external magnetic field, such a system supports collective modes, which correspond to coupled oscillations of the uniform and valley-staggered magnetizations. These modes can be detected via both zero-field electron spin resonance (ESR) and zero-field electric-dipole spin resonance (EDSR), with EDSR response coming solely from Rashba SOC. We analyze the effect of electron-electron interaction within the Fermi- liquid kinetic equation and show that the interaction splits both the ESR and EDSR peaks into two. The magnitude of splitting and the relative weights of the resonances can be used to extract the spin-orbit coupling constants and many-body interaction parameters that may not be accessible by other methods.