Charge disproportionation and the pressure-induced insulator–metal transition in cubic perovskite PbCrO 3
The perovskite PbCrO 3 is an antiferromagnetic insulator. But, the fundamental interactions leading to the insulating state in this single-valent perovskite are unclear. Moreover, the origin of the unprecedented volume drop observed at a modest pressure of P = 1.6 GPa remains an outstanding problem. Our report shows a variety of in situ pressure measurements including electron transport properties, X-ray absorption spectrum, and crystal structure study by X-ray and neutron diffraction. These studies reveal key information leading to the elucidation of the physics behind the insulating state and the pressure-induced transition. Furthermore, we argue that a charge disproportionation 3Cr 4+ → 2Cr 3+ + Cr 6+ in association with the 6s-p hybridization on the Pb 2+ is responsible for the insulating ground state of PbCrO 3 at ambient pressure and the charge disproportionation phase is suppressed under pressure to give rise to a metallic phase at high pressure. The model is well supported by density function theory plus the correlation energy U (DFT + U) calculations.
- Univ. of Texas, Austin, TX (United States). Materials Science and Engineering Program and Texas Materials Inst.; Chinese Academy of Sciences (CAS), Beijing (China). Inst. of Physics; Univ. of Tokyo (Japan). Inst. for Solid State Physics
- Univ. of Texas, Austin, TX (United States). Chemical Engineering and Texas Materials Inst.
- Univ. of Texas, Austin, TX (United States). Materials Science and Engineering Program and Texas Materials Inst.
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
- Univ. of Tokyo (Japan). Inst. for Solid State Physics
- Publication Date:
- OSTI Identifier:
- Grant/Contract Number:
- AC05-00OR22725; AC02-06CH11357
- Published Article
- Journal Name:
- Proceedings of the National Academy of Sciences of the United States of America
- Additional Journal Information:
- Journal Volume: 112; Journal Issue: 6; Journal ID: ISSN 0027-8424
- National Academy of Sciences, Washington, DC (United States)
- Research Org:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Org:
- Country of Publication:
- United States
- 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; high pressure; perovskite; insulator-metal transition; charge disproportionation; LARGE-VOLUME; MICROSTRUCTURE; SPECTROSCOPY; CHROMIUM; CRYSTAL
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