Hybridization-Switching Induced Mott Transition in ABO_{3} Perovskites

Area of Science:

• Solid State Physics
• Materials Science
• Computational Chemistry

Background:

• ABO3 perovskites are crucial materials with diverse electronic properties.
• Some perovskites exhibit Mott insulating states due to strong electron correlations.
• Understanding the mechanisms driving these states is key for materials design.

Purpose of the Study:

• To introduce and investigate the "hybridization-switching induced Mott transition" mechanism.
• To explore its relevance in ABO3 perovskites with extended 6s orbitals and ligand holes.
• To elucidate the role of pressure in inducing transitions.

Main Methods:

• Ab initio electronic structure calculations.
• Slave rotor theory.
• Analysis of phonon-driven instabilities and electron correlations.

Main Results:

• Identified a breathing phonon driving an A-site to oxygen hybridization-wave instability.
• Demonstrated that this instability, coupled with B-site correlations, triggers a Mott insulating state.
• Showed pressure-induced insulator-to-metal transition with colossal volume collapse via ligand hybridization switching.

Conclusions:

• The "hybridization-switching induced Mott transition" is a novel mechanism governing electronic states in specific perovskites.
• This mechanism explains pressure-induced metallization and volume collapse.
• The findings are applicable to BiNiO3, PbCrO3, and related materials.