Non-Fermi liquid behavior and scaling of low frequency suppression in optical conductivity spectra of CaRuO${}_3$

Abstract

Optical conductivity spectra $\ddot{I}{ƒ}_1(\ddot{I}‰)$ of paramagnetic CaRuO${}_3$ are investigated at various temperatures. At T=10 K, it shows a non-Fermi liquid behavior of $\ddot{I}{ƒ}_1(\ddot{I}‰)\sim 1/\ddot{I}{‰}^{\frac{1}{2}}$, similar to the case of a ferromagnet SrRuO${}_3$. As the temperature ($T$) is increased, on the other hand, $\ddot{I}{ƒ}_1(\ddot{I}‰)$ in the low frequency region is progressively suppressed, deviating from the $1/ω^{\frac 12%}$-dependence. Interestingly, the suppression of $\ddot{I}{ƒ}_1(\ddot{I}‰)$ is found to scale with $\ddot{I}‰/T$ at all temperatures. The origin of the scaling behavior coupled with the non-Fermi liquid behavior is discussed.

4 pages, 3 figures