Propagating charge carrier plasmon in Sr2RuO4

TL;DR

This study investigates charge carrier plasmon excitations in Sr2RuO4 using electron energy-loss spectroscopy, revealing that long-wavelength plasmons are resilient quasiparticles unaffected by correlations.

Contribution

It provides the first detailed analysis of plasmon dispersion and decay mechanisms in Sr2RuO4, linking experimental results with RPA calculations and clarifying the nature of plasmon damping.

Findings

Plasmon dispersion aligns with RPA calculations using unrenormalized band structure.

The plasmon width remains constant at long wavelengths, indicating decay into inter-band transitions.

Long-wavelength plasmons near 1 eV are caused by resilient quasiparticles, not quantum critical fluctuations.

Abstract

We report on studies of charge carrier plasmon excitations in Sr2RuO4 by transmission Electron Energy-Loss Spectroscopy. In particular, we present results on the plasmon dispersion and its width as a function of momentum transfer. The dispersion can be qualitatively explained in the framework of RPA calculations, using an unrenormalized tight-binding band structure. The constant long-wavelength width of the plasmon indicates, that it is caused by a decay into inter-band transition and not by quantum critical fluctuations. The results from these studies on a prototypical bad metal system show that the long-wavelength plasmon excitations near 1 eV are caused by resilient quasiparticles and are not influenced by correlation effects.