Electrical Resistivity in Oxide Semiconductor BaBi_1−xMo_xO₃

Abstract

Single crystals of BaBi_1−xMo_xO₃ were grown with x up to 0.15. The electrical resistivity showed an activation type temperature dependence. The activation energy at room temperature increases from 0.1 to 0.24 (eV) with increasing x to 0.15. Near 0.05 of x transition from monoclinic to orthorhombic structures was observed. The corresponding change in the resistivity was observed in the range of 0.03<x<0.05. The activation energy increases when the crystal symmetry increases with increasing temperature, or with increasing molybdenum concentration. Such results rule out the picture of CDW-gap semiconductor. Instead we suggest the existence of localization gap at the Fermi surface, which comes from the disorder of Bi³⁺ and Bi⁵⁺, from impurities, or from oxygen vacancies.