High-resolution temperature-dependent photoemission study of metal-insulator transition of Y1-xCaxTiO3

Temperature-dependent high-resolution photoemission spectroscopy has been p erformed on Y1-xCaxTiO3 (x = 0.37, 0.39, and 0.41) single crystals. Ti 3d p hotoemission spectra have an incoherent part, indicating electrons in the T i 3d bands are strongly correlated. Although the temperature dependence of the incoherent part at 150 K for the present samples is continuous and near ly the same, the spectral intensity near E-F of the x = 0.39 composition cl early shows the metal-insulator transition at similar to 150 K, indicating the importance of the carrier density in the Ti 3d bands. (C) 2000 Elsevier Science B.V. All rights reserved.