Metal-insulator transition in nearly stoichiometric cavo3

Abstract

A metal-to-insulator (MI) transition in perovskite-type vanadium oxide CaVOy in the vicinity of oxygen stoichiometry is reported. In spite of good metallic conductivity for stoichiometric CaV07 (y=3.00), very slight oxidation (y = 3.05)causes the system to be insulating but does not induce any significant structural changes. This type of MI transition is contrary to that reported on another d1 system LaTiO^, which is a Mott-Hubbard insulator for y=3.00 but becomes metallicby oxidation. We suggest that in CaVO^, extra oxygens primarily induce additional scattering which causes the metallicCaV03 to be insulating. © 1993 The Japan Society of Applied Physics.