Hybridization-Switching Induced Mott Transition in AB O3 Perovskites

We propose the concept of a "hybridization-switching induced Mott transition" which is relevant to a broad class of ABO3 perovskite materials including BiNiO3 and PbCrO3 that feature extended 6s orbitals on the A-site cation (Bi or Pb), and a strong A-O covalency induced ligand hole. Using ab initio electronic structure and slave rotor theory calculations, we show that such systems exhibit a breathing phonon driven A-site to oxygen hybridization-wave instability which conspires with strong correlations on the B-site transition metal ion (Ni or Cr) to trigger a Mott insulating state. This class of systems is shown to undergo a pressure induced insulator to metal transition accompanied by a colossal volume collapse due to ligand hybridization switching.