Electron Spin Resonance in a Two-Dimensional Fermi Liquid with Spin-Orbit Coupling

TL;DR

This paper demonstrates that electron spin resonance in a 2D Fermi liquid with spin-orbit coupling reveals collective modes and many-body effects, challenging the view of ESR as a purely single-particle phenomenon.

Contribution

It shows that ESR in a 2D Fermi liquid with SOC can probe collective modes and many-body physics, expanding its interpretative scope.

Findings

ESR probes up to three collective chiral-spin modes.

ESR can detect many-body correlations in the presence of SOC.

The magnetic field influences the nature of the ESR modes.

Abstract

Electron spin resonance (ESR) is usually interpreted as a single-particle phenomenon protected from the effect of many-body correlations. We show that this is not the case in a two-dimensional Fermi liquid (FL) with spin-orbit coupling (SOC). Depending on whether the magnetic field is below or above some critical value, ESR in such a system probes up to three collective chiral-spin modes, augmented by the presence of the field, or the Larmor mode, augmented both by SOC and FL renormalizations. We argue that ESR can be used as a probe not only for SOC but also for many-body physics.