Ca1-xSrxVO3 is a Mott-Hubbard-type correlated electron system whose bandwidth can be varied by the V-O-V bond angle, but the actual effect of bandwidth control on the electronic structure has been controversial in previous photoemission experiments. In this work, band dispersions and Fermi surfaces of SrVO3 and CaVO3 are studied by angle-resolved photoemission spectroscopy. Near the Fermi level (EF), three bands forming cylindricalFermi surfaces derived from the three V 3d t2g orbitals have been observed. The observed band widths for both compounds are almost half of those predicted by local-density-approximation band-structure calculation, confirming mass renormalization caused by electron correlation. It has been clearly demonstrated that the width of the d band in CaVO3 is narrower than that in SrVO3, qualitatively consistent with the result of band-structure calculation. Roles of the orthorhombic lattice distortion and electron correlation in the observed band narrowing are discussed.
تحميل البحث