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

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 spin 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 arising solely due to Rashba SOC. We analyze the effect of electronelectron 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.

Automated summary

Collective spin excitations in graphene with proximity-induced spin-orbit coupling of the Rashba and valley-Zeeman types are investigated. It is found that even in the absence of an external magnetic field, the system supports collective spin modes, detectable via zero-field electron spin resonance (ESR) and zero-field electric-dipole spin resonance (EDSR). The effects of electron-electron interaction are analyzed, leading to splitting of both ESR and EDSR peaks which can be used to extract spin-orbit coupling constants and many-body interaction parameters.