Coexistence of two components in the optical spectra of CeTiO_3.04 in the antiferromagnetic metallic phase

The optical spectra of CeTiO_3.04, which undergoes a phase transition from a paramagnetic metal to an antiferromagnetic metal, are investigated with changing temperature (T). In the paramagnetic phase, optical conductivity shows a T-dependent feature up to 1 eV, which can be attributed to the T-dependent scattering rate. In the antiferromagnetic phase, on the other hand, optical conductivity reduces its low-energy weight below 0.4 eV, but no gaplike structure appears. A two-component model, where the spectrum is a sum of a metallic and an insulating component, gives a simple explanation for the change of the optical spectra in the antiferromagnetic metallic phase.