High-pressure phases of VO 2 from the combination of Raman scattering and ab initio structural search - Université Claude Bernard Lyon 1 Accéder directement au contenu
Article Dans Une Revue Physical Review B Année : 2018

High-pressure phases of VO 2 from the combination of Raman scattering and ab initio structural search

Résumé

Despite more than 50 years of investigation, the understanding of the metal-insulator transition in $VO_2$ 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.
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Dates et versions

hal-02364236 , version 1 (14-11-2019)

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Victor Balédent, Tiago Cerqueira, Rafael Sarmiento-Perez, Abhay Shukla, Christophe Bellin, et al.. High-pressure phases of VO 2 from the combination of Raman scattering and ab initio structural search. Physical Review B, 2018, 97 (2), pp.024107. ⟨10.1103/PhysRevB.97.024107⟩. ⟨hal-02364236⟩
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