Issue
EPL
Volume 78, Number 1, April 2007
Article Number 17002
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/78/17002
Published online 13 March 2007
EPL, 78 (2007) 17002
DOI: 10.1209/0295-5075/78/17002

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

K. Maiti, R. S. Singh and V. R. R. Medicherla

Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research - Homi Bhabha Road, Colaba, Mumbai 400005, India

kbmaiti@tifr.res.in

received 13 November 2006; accepted in final form 13 February 2007; published April 2007
published online 13 March 2007

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.

PACS
71.10.Hf - Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems.
63.20.Kr - Phonon-electron and phonon-phonon interactions.
71.45.Gm - Exchange, correlation, dielectric and magnetic response functions, plasmons.

© Europhysics Letters Association 2007