High-resolution photoemission spectroscopy (HRPES) was performed on (Formula presented) ((Formula presented)=0.00, 0.03, and 0.04), which has been considered as the prototype of the Mott-Hubbard model for the metal-insulator transition (MIT). The density of states at the Fermi level (Formula presented) observed by HRPES is one order of magnitude smaller than that of the band calculation based on the local-density approximation. We observed no distinguishable sharp structure at (Formula presented) for hole-doped (Formula presented) at 15 K as well as negligible temperature-dependence of the HRPES spectrum of (Formula presented) between 200 and 300 K. The analysis of the V 3(Formula presented) spectrum with a local self-energy gives a too large quasiparticle effective mass compared to the specific-heat measurement, which implies the importance of spatial fluctuations near the MIT. All these facts strongly question the applicability of the dynamical mean-field theory of the Hubbard model to the (Formula presented) system.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 1998 1 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics