Non-Fermi liquid behavior and scaling of the low-frequency suppression in the optical conductivity spectra of CaRuO 3

Optical conductivity spectra σ 1 (ω) of paramagnetic CaRuO 3 are investigated at various temperatures. At T=10 K, it shows a non-Fermi-liquid behavior of σ 1 (ω)∼1/ω 1 / 2 , similar to the case of a ferromagnet SrRuO 3 . As the temperature (T) is increased, on the other hand, σ 1 (ω) in the low-frequency region is progressively suppressed, deviating from the 1/ω 1 / 2 dependence. Interestingly, the suppression of σ 1 (ω) is found to scale with ω/T at all temperatures. The origin of the ω/T scaling behavior coupled with the non-Fermi-liquid behavior is discussed.