Pressure-induced phase transitions and metallization in VO2

Bai, L., Li, Q., Corr, S. A., Meng, Y., Park, C., Sinogeikin, S. V., Ko, C., Wu, J. and Shen, G. (2015) Pressure-induced phase transitions and metallization in VO2. Physical Review B, 91(10), 104110. (doi: 10.1103/PhysRevB.91.104110)

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Abstract

We report the results of pressure-induced phase transitions and metallization in VO2 based on synchrotron x-ray diffraction, electrical resistivity, and Raman spectroscopy. Our isothermal compression experiments at room temperature and 383 K show that the room temperature monoclinic phase (M1,P21/c) and the high-temperature rutile phase (R,P42/mnm) of VO2 undergo phase transitions to a distorted M1 monoclinic phase (M1′,P21/c) above 13.0 GPa and to an orthorhombic phase (CaCl2-like, Pnnm) above 13.7 GPa, respectively. Upon further compression, both high-pressure phases transform into a new phase (phase X) above 34.3 and 38.3 GPa at room temperature and 383 K, respectively. The room temperature M1−M1′ phase transition structurally resembles the R−CaCl2 phase transition at 383 K, suggesting a second-order displacive type of transition. Contrary to previous studies, our electrical resistivity results, Raman measurements, as well as ab initio calculations indicate that the new phase X, rather than the M1′ phase, is responsible for the metallization under pressure. The metallization mechanism is discussed based on the proposed crystal structure.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Corr, Professor Serena
Authors: Bai, L., Li, Q., Corr, S. A., Meng, Y., Park, C., Sinogeikin, S. V., Ko, C., Wu, J., and Shen, G.
College/School:College of Science and Engineering > School of Computing Science
Journal Name:Physical Review B
Publisher:American Physical Society
ISSN:1098-0121
ISSN (Online):1550-235X
Copyright Holders:Copyright © 2015 American Physical Society
First Published:First published in Physical Review B 91(10):104110
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
643201Microwave processing for fast, green preparation of insertion electrodesSerena CorrEngineering & Physical Sciences Research Council (EPSRC)EP/K029290/1SCHOOL OF CHEMISTRY