Structural and electronic recovery pathways of a photoexcited ultrathin VO2 film

Haidan Wen, Lu Guo, Eftihia Barnes, June Hyuk Lee, Donald A. Walko, Richard D. Schaller, Jarrett A. Moyer, Rajiv Misra, Yuelin Li, Eric M. Dufresne, Darrell G. Schlom, Venkatraman Gopalan, John W. Freeland

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Abstract

The structural and electronic recovery pathways of a photoexcited ultrathin vanadium dioxide (VO2) film at nanosecond time scales have been studied using time-resolved x-ray diffraction and transient optical absorption techniques. The recovery pathways from the tetragonal metallic phase to the monoclinic insulating phase are highly dependent on the optical pump fluence. At pump fluences higher than the saturation fluence of 14.7 mJ/cm2, we observed a transient structural state with lattice parameter larger than that of the tetragonal phase, which is decoupled from the metal-to-insulator phase transition. Subsequently, the photoexcited VO2 film recovered to the ground state at characteristic times dependent upon the pump fluence as a result of heat transport from the film to the substrate. We present a procedure to measure the time-resolved film temperature by correlating photoexcited and temperature-dependent x-ray diffraction measurements. A thermal transport model that incorporates changes of the thermal parameters across the phase transition reproduces the observed recovery dynamics. The optical excitation and fast recovery of ultrathin VO2 films provides a practical method to reversibly switch between the monoclinic insulating and tetragonal metallic state at nanosecond time scales.

Original languageEnglish
Article number165424
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume88
Issue number16
DOIs
Publication statusPublished - Oct 25 2013

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Wen, H., Guo, L., Barnes, E., Lee, J. H., Walko, D. A., Schaller, R. D., Moyer, J. A., Misra, R., Li, Y., Dufresne, E. M., Schlom, D. G., Gopalan, V., & Freeland, J. W. (2013). Structural and electronic recovery pathways of a photoexcited ultrathin VO2 film. Physical Review B - Condensed Matter and Materials Physics, 88(16), [165424]. https://doi.org/10.1103/PhysRevB.88.165424