HIGH-RESOLUTION PHOTOEMISSION-STUDY OF V2-YO3

High-resolution photoemission spectroscopy (HRPES) was performed on V2 -yO3 (y=0.00, 0.03, and 0.04), which lias been considered as the proto type of the Mott-Hubbard model for the metal-insulator transition (MIT ). The density of states at the Fermi level (E-F) observed by HRPES is one order of magnitude smaller than that of the band calculation base d on the local-density approximation. We observed no distinguishable s harp structure at E-F for hole-doped V1.96O3 at 15 K as well as neglig ible temperature-dependence of the HRPES spectrum of V2O3 between 200 and 300 K. The analysis of the V 3d spectrum with a local self-energy gives a too large quasiparticle effective mass compared to the specifi c-heat measurement, which implies the importance of spatial fluctuatio ns near the MIT. All these facts strongly question the applicability o f the dynamical mean-field theory of the Hubbard model to the V2-yO3 s ystem.