Two-component electronic phase separation in the doped Mott insulator Y1−xCaxTiO3

Abstract

The Mott insulator-metal transition has been the subject of intense research in condensed matter physics. Here, the authors study this transition in the prototypical perovskite oxide Y(Ca)TiO${}_{3}$, using a combination of x-ray absorption spectroscopy measurements and density functional theory calculations. They uncover electronic phase separation into hole-poor Mott-insulating and hole-rich metallic regions, i.e., an inherent first-order and percolative nature of the transition that occurs at nonzero hole doping.