Metal-Insulator Transition and Local Structure of V2O3

A.I. Frenkel; E.A. Stern; F.A. Chudnovsky

doi:doi:10.1051/jp4:19972137

Numéro		J. Phys. IV France Volume 7, Numéro C2, Avril 1997 Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure


Page(s)		C2-1061 - C2-1063
DOI		https://doi.org/10.1051/jp4:19972137

Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure

J. Phys. IV France 7 (1997) C2-1061-C2-1063
DOI: 10.1051/jp4:19972137

Metal-Insulator Transition and Local Structure of V₂O₃

A.I. Frenkel¹, E.A. Stern¹ and F.A. Chudnovsky²

¹ Physics Department Box 351560, University of Washington, Seattle, WA 98195-1560, U.S.A.
² Ioffe Physical-Technical Institute, 19402 Saint Petersburg, Russia

Abstract
According to diffraction measurements of the average structure, V₂O₃ changes on heating from monoclinic to trigonal, accompanied by a 1.4% volume decrease, where some V - V distances decrease by about 0.11 Å, favoring the Mott - Hubbard mechanism of the phase transition from insulator to metal. Our polarized XAFS measurements of the local structure of the single crystal V₂O₃ show the same decrease in volume but no change in local symmetry in the transition, indicating that the phase transition contains a significant order - disorder component, contrary to the purely displacive model based on diffraction results. XANES measurements found that the onset of the 1s→"3d" transition in the insulator shifts towards lower energies by about 1eV in the metal, consistent with the shielding of the core hole potential by conducting electrons.