Unoccupied electronic structure of Y1-xCaxTiO3 investigated by inverse photoemission spectroscopy

Arita Masashi

Sato Hitoshi

Higashi Masayuki

Yoshikawa Kunta

Shimada Kenya

Nakatake Masashi

Ueda Yuko

Namatame Hirofumi

Taniguchi Masaki

Tsubota Masami

Iga Fumitoshi

Takabatake Toshiro

Physical Review B - Condensed Matter and Materials Physics

We have studied the unoccupied electronic structure of the band insulator CaTiO3, the Mott insulator YTiO3, and Y0.61Ca0.39TiO3 with a metal-insulator transition (MIT) around 150 K by means of Ti 3p-3d resonant inverse photoemission spectroscopy (RIPES). The Ti 3d partial density of states of CaTiO3 deduced from the on- and off-resonance RIPES spectra is in good agreement with results of a band-structure calculation, while that of YTiO3 is explained based on a calculation with the dynamical mean-field theory taking into account an electron correlation. In the case of Y0.61Ca0.39TiO3, we have successfully observed the temperature dependence of RIPES spectra across MIT; the intensity of the incoherent part (a remnant of the upper Hubbard bands) relative to the coherent part (quasiparticle bands) is reduced with decreasing temperature from the insulator to metal phases.

yttrium compounds

calcium compounds

band structure

inverse photoemission spectra

metal-insulator transition

electronic density of states

electron correlations

eng

American Physical Society

Copyright (c) 2007 The American Physical Society.

[ISSN] 0163-1829

[DOI] 10.1103/PhysRevB.75.205124

[NCID] AA11187113

[DOI] http://dx.doi.org/10.1103/PhysRevB.75.205124