Reflectance and resistivity of barely metallicLaTiO3

The absolute reflectance of ${\mathrm{LaTiO}}_3$ was measured from 70 to 17 500 ${\mathrm{cm}}^{\mathrm{-}1}$. The Kramers-Kronig-derived optical conductivity shows three sharp phonon structures near 170, 340, and 540 ${\mathrm{cm}}^{\mathrm{-}1}$ that are explained by a factor-group analysis. The midinfrared spectrum is dominated by a broad absorption band with an onset near 600 ${\mathrm{cm}}^{\mathrm{-}1}$. A comparison of reflectance and resistivity measurements indicates that the dc mobility is less than 3 ${\mathrm{cm}}^2$/V s at 300 K, and thus the carriers are somewhat localized.