Abstract
Tensile strain along the cR axis in epitaxial VO2 films raises the temperature of the metal insulator transition and is expected to stabilize the intermediate monoclinic M2 phase. We employ surface-sensitive x-ray spectroscopy to distinguish from the TiO2 substrate and identify the phases of VO2 as a function of temperature in epitaxial VO2/TiO2 thin films with well-defined biaxial strain. Although qualitatively similar to our Landau-Ginzburg theory predicted phase diagrams, the M2 phase is stabilized by nearly an order of magnitude more strain than expected for the measured temperature window. Our results reveal that the elongation of the cR axis is insufficient for describing the transition pathway of VO2 epitaxial films and that a strain induced increase of electron correlation effects must be considered.
Original language | English |
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Article number | 085105 |
Journal | Physical Review B |
Volume | 94 |
Issue number | 8 |
DOIs | |
Publication status | Published - 5 Aug 2016 |
Bibliographical note
Funding Information:A.M.G. acknowledges Diamond Light Source for the co-sponsorship of a studentship on the EPSRC Centre for Doctoral Training in Molecular Modeling and Materials Science (EP/L015862/1). B.J.M. acknowledges support from the Royal Society (UF130329). Y.G., F.X., and L.Q.C. acknowledge support from the Penn State MRSEC, Center for Nanoscale Science, under the award NSF DMR-1420620.
Publisher Copyright:
© 2016 American Physical Society.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics