Charge disproportionation and the pressure-induced insulator-metal transition in cubic perovskite PbCrO^sub 3

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 112; no. 6; p. 1670
• Main Authors: Cheng, Jinguang, Kweon, K E, Larregola, S A, Ding, Yang, Shirako, Y, Marshall, L G, Li, Z-Y, Li, X, dos Santos, António M, Suchomel, M R, Matsubayashi, K, Uwatoko, Y, Hwang, G S, Goodenough, John B, Zhou, J-S
• Format: Journal Article
• Language: English
• Published: Washington National Academy of Sciences 10-02-2015
• Subjects: Crystal structure; Electron transfer; Perovskite; Physical properties; Pressure; Spectrum analysis
• ISSN: 0027-8424; 1091-6490

The perovskite PbCrO3 is an antiferromagnetic insulator. However, 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. We report 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. We argue that a charge disproportionation ... in association with the 6s-p hybridization on the Pb2+ is responsible for the insulating ground state of PbCrO3 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. (ProQuest: ... denotes formulae/symbols omitted.)