Another mechanism for the insulator-metal transition observed in Mott insulators

Journal Article · Mon Apr 28 04:00:00 EDT 2008 · Phys. Rev. B

DOI:https://doi.org/10.1103/PhysRevB.77.155112· OSTI ID:1006575

Gavriliuk, Alexander G; Struzhkin, Viktor V; Lyubutin, Igor S; Ovchinnikov, Sergey G; Hu, Michael Y; Chow, Paul ^[1]

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1. Russ. Acad. Sci.

The two widely accepted mechanisms of the insulator-metal Mott-Hubbard transitions which have been considered up until now are driven by the band-filling or bandwidth effects. We found a different mechanism of the Mott-Hubbard insulator-metal transition, which is controlled instead by the changes in the Mott-Hubbard energy U. In contrast to the changes in the bandwidth W in the 'bandwidth control' scenario or to the variations of the band-filling n parameter in the 'band-filling' scenario, a dramatic decrease in the Mott-Hubbard energy U plays the key role in this mechanism. We have experimentally observed this type of the insulator metal transition in the transition metal oxide BiFeO{sub 3}. The decrease in the Mott-Hubbard energy is caused by the high-spin-low-spin crossover in the electronic d shell of 3d transition metal ion Fe{sup 3+} with d{sup 5} configuration under high pressure. The pressure-induced spin crossover in BiFeO{sub 3} was investigated and confirmed by synchrotron x-ray diffraction, nuclear forward scattering, and x-ray emission methods. The insulator-metal transition at the same pressures was found by the optical absorption and dc resistivity measurements.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006575
• Journal Information: Phys. Rev. B, Journal Name: Phys. Rev. B Journal Issue: 2008 Vol. 77; ISSN 1098-0121
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
BISMUTH OXIDES
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PHASE TRANSFORMATIONS