SYSTEMATIC CHANGE OF SPECTRAL-FUNCTION OBSERVED BY CONTROLLING ELECTRON CORRELATION IN CA1-XSRXVO3 WITH FIXED 3D(1) CONFIGURATION

By using ultra-violet photoemission spectroscopy (UPS) and soft x-ray absorption spectroscopy (XAS), we have observed a systematic change of the spectral function around the Fermi level in the perovskite-type c onductive 3d(1) system, Ca1-xSrxVO3. When we decrease the Sr concentra tion (x) from 1 to 0 in Ca(1-x)SrxVO(3), UPS and XAS intensities near the Fermi level decrease, and the reduced spectral weight is transferr ed to high energy part about 2 eV below and above Fermi level. The hig h energy features are thought to correspond to the remnants of lower a nd upper Hubbard bands, and the spectral weight within similar to 1eV of Fermi level is assigned to the quasiparticle excitations or renorma lized 3d-band. That is, the observed systematic spectral change indica tes the opening of Mott-Hubbard gap.