Observation of particle hole asymmetry and phonon excitations in non-Fermi liquid systems: A high-resolution photoemission study of ruthenates

TL;DR

This study uses high-resolution photoemission spectroscopy to compare electronic states and phonon excitations in non-Fermi liquid CaRuO3 and Fermi liquid SrRuO3, revealing particle-hole asymmetry and phonon signatures in CaRuO3.

Contribution

It provides new insights into particle-hole asymmetry and phonon excitations in non-Fermi liquid systems using high-resolution photoemission.

Findings

Particle-hole asymmetry observed in CaRuO3

Phonon excitations detected in CaRuO3 at finite temperatures

Contrast with SrRuO3 showing Fermi liquid behavior

Abstract

We investigate the temperature evolution of the electronic states in the vicinity of the Fermi level of a non-Fermi liquid (NFL) system, CaRuO3 using ultra high-resolution photoemission spectroscopy; isostructural SrRuO3 exhibiting Fermi liquid behavior despite similar electron interaction parameters as that of CaRuO3, is used as a reference. High-energy resolution in this study helps to reveal particle-hole asymmetry in the excitation spectra of CaRuO3 in contrast to that in SrRuO3. In addition, we observe signature of phonon excitations in the photoemission spectra of CaRuO3 at finite temperatures while these are weak in SrRuO3.