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High-pressure phases of VO2 from the combination of Raman scattering and ab initio structural search

TitleHigh-pressure phases of VO2 from the combination of Raman scattering and ab initio structural search
Publication TypeJournal Article
Year of Publication2018
AuthorsBaledent, V., Cerqueira T. T. F., Sarmiento-Perez R., Shukla A., Bellin C., Marsi M., Itie J. - P., Gatti M., Marques M. A. L., Botti S., & Rueff J. - P.
Abstract

Despite more than 50 years of investigation, the understanding of the metal-insulator transition in VO2\textbackslash{} remains incomplete and requires additional experimental and theoretical works. Using Raman scattering under pressure, we first confirm the known transition around 11 GPa affecting the V orbital occupancy in the absence of structural changes. Moreover, we disclose a transition around 19 GPa involving the V orbitals together with a structural distortion, revealed by the splitting of a phonon branch associated with the V chains. The high-pressure metallic X phase is found to be of low symmetry and becomes the lowest-enthalpy structure at high pressure by ab initio structural prediction calculations. In contrast to a well-established picture of the metal-insulator transition (i.e., the Peierls transition), the high-pressure metallic phase here is of lower symmetry than the ambient pressure insulating phase.

JournalPHYSICAL REVIEW B
Volume97
Pagination024107
DOI10.1103/PhysRevB.97.024107
Citation Key ISI:000423118400002