Frequency and temperature dependence of conductivity for perovskite titanates

Frequency- and temperature-dependent conductivity has been studied by optical spectroscopy for perovskite titanates, which are typical three-dimensional correlated metals. Extended Drude analysis of the data indicates that only one parameter, the $T^2$ coefficient of the scattering rate, dominates the temperature dependence of conductivity over a wide energy range (from dc to $\sim 1\mathrm{eV}).\mathrm{}$ This result is consistent with the Fermi-liquid theory in the low-frequency limit, and can be regarded as a prototypical behavior of correlated metals.