Larmor precession in strongly correlated itinerant electron systems

TL;DR

This paper uses dynamical mean-field theory to analyze collective Larmor precession in strongly correlated itinerant electron systems, revealing detailed spin excitation spectra and damping mechanisms.

Contribution

It provides a detailed theoretical investigation of spin wave dynamics and damping in strongly correlated metals using advanced many-body techniques.

Findings

Identification of dispersive Larmor mode and Stoner damping effects

Extraction of momentum-resolved spin wave damping

Validation of Ward identity for accurate correlation effects

Abstract

Many-electron systems undergo a collective Larmor precession in the presence of a magnetic field. In a paramagnetic metal, the resulting spin wave provides insight into the correlation effects generated by the electron-electron interaction. Here, we use dynamical mean-field theory to investigate the collective Larmor precession in the strongly correlated regime, where dynamical correlation effects such as quasiparticle lifetimes and non-quasiparticle states are essential. We study the spin excitation spectrum, which includes a dispersive Larmor mode as well as electron-hole excitations that lead to Stoner damping. We also extract the momentum-resolved damping of slow spin waves. The accurate theoretical description of these phenomena relies on the Ward identity, which guarantees a precise cancellation of self-energy and vertex corrections at long wavelengths. Our findings pave the way towards a better understanding of spin wave damping in correlated materials.