The nature of photoinduced phase transition and metastable states in vanadium dioxide

Zhensheng Tao, Faran Zhou, Tzong Ru T Han, David Torres, Tongyu Wang, Nelson Sepulveda, Kiseok Chang, Margaret Young, Richard R. Lunt, Chong Yu Ruan

    Research output: Contribution to journalArticle

    • 6 Citations

    Abstract

    Photoinduced threshold switching processes that lead to bistability and the formation of metastable phases in photoinduced phase transition of VO2 are elucidated through ultrafast electron diffraction and diffusive scattering techniques with varying excitation wavelengths. We uncover two distinct regimes of the dynamical phase change: A nearly instantaneous crossover into an intermediate state and its decay led by lattice instabilities over 10 ps timescales. The structure of this intermediate state is identified to be monoclinic, but more akin to M2 rather than M1 based on structure refinements. The extinction of all major monoclinic features within just a few picoseconds at the above-threshold-level (∼20%) photoexcitations and the distinct dynamics in diffusive scattering that represents medium-range atomic fluctuations at two photon wavelengths strongly suggest a density-driven and nonthermal pathway for the initial process of the photoinduced phase transition. These results highlight the critical roles of electron correlations and lattice instabilities in driving and controlling phase transformations far from equilibrium.

    Original languageEnglish (US)
    Article number38514
    JournalScientific Reports
    Volume6
    DOIs
    StatePublished - Dec 16 2016

    Profile

    thresholds
    scattering
    wavelengths
    dioxides
    photoexcitation
    metastable state
    vanadium
    phase transformations
    crossovers
    extinction
    electron diffraction
    photons
    decay
    excitation
    electrons

    ASJC Scopus subject areas

    • General

    Cite this

    The nature of photoinduced phase transition and metastable states in vanadium dioxide. / Tao, Zhensheng; Zhou, Faran; Han, Tzong Ru T; Torres, David; Wang, Tongyu; Sepulveda, Nelson; Chang, Kiseok; Young, Margaret; Lunt, Richard R.; Ruan, Chong Yu.

    In: Scientific Reports, Vol. 6, 38514, 16.12.2016.

    Research output: Contribution to journalArticle

    Tao Z, Zhou F, Han TRT, Torres D, Wang T, Sepulveda N et al. The nature of photoinduced phase transition and metastable states in vanadium dioxide. Scientific Reports. 2016 Dec 16;6. 38514. Available from, DOI: 10.1038/srep38514

    Tao, Zhensheng; Zhou, Faran; Han, Tzong Ru T; Torres, David; Wang, Tongyu; Sepulveda, Nelson; Chang, Kiseok; Young, Margaret; Lunt, Richard R.; Ruan, Chong Yu / The nature of photoinduced phase transition and metastable states in vanadium dioxide.

    In: Scientific Reports, Vol. 6, 38514, 16.12.2016.

    Research output: Contribution to journalArticle

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    AU - Sepulveda,Nelson

    AU - Chang,Kiseok

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