We propose the concept of a “hybridization-switching induced Mott transition” which is relevant to a broad class of $AB{\mathrm{O}}_3$ perovskite materials including ${\mathrm{BiNiO}}_3$ and ${\mathrm{PbCrO}}_3$ that feature extended $6s$ orbitals on the $A$-site cation (Bi or Pb), and a strong $A\text{−}\mathrm{O}$ 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.

• Received 25 January 2018
• Revised 20 May 2018

DOI:https://doi.org/10.1103/PhysRevLett.122.016404