Unoccupied electronic structure of Y1-xCaxTiO3 investigated by inverse photoemission spectroscopy
PhysRevB_75_205124.pdf 430 KB
inverse photoemission spectra
electronic density of states
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.
Physical Review B - Condensed Matter and Materials Physics
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American Physical Society
Copyright (c) 2007 The American Physical Society.
Graduate School of Science
Graduate School of Advanced Sciences of Matter
Hiroshima Synchrotron Radiation Center