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

Photoinduced threshold switching processes that lead to bistability and the formation of metastable phases in photoinduced phase transition of VO(2) are elucidated through ultrafast electron diffraction and diffusive scattering techniques with varying excitation wavelengths. We uncover two distinct...

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Autores principales: Tao, Zhensheng, Zhou, Faran, Han, Tzong-Ru T., Torres, David, Wang, Tongyu, Sepulveda, Nelson, Chang, Kiseok, Young, Margaret, Lunt, Richard R., Ruan, Chong-Yu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5159834/
https://www.ncbi.nlm.nih.gov/pubmed/27982066
http://dx.doi.org/10.1038/srep38514
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author Tao, Zhensheng
Zhou, Faran
Han, Tzong-Ru T.
Torres, David
Wang, Tongyu
Sepulveda, Nelson
Chang, Kiseok
Young, Margaret
Lunt, Richard R.
Ruan, Chong-Yu
author_facet Tao, Zhensheng
Zhou, Faran
Han, Tzong-Ru T.
Torres, David
Wang, Tongyu
Sepulveda, Nelson
Chang, Kiseok
Young, Margaret
Lunt, Richard R.
Ruan, Chong-Yu
author_sort Tao, Zhensheng
collection PubMed
description Photoinduced threshold switching processes that lead to bistability and the formation of metastable phases in photoinduced phase transition of VO(2) 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 M(2) rather than M(1) 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.
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spelling pubmed-51598342016-12-21 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 Sci Rep Article Photoinduced threshold switching processes that lead to bistability and the formation of metastable phases in photoinduced phase transition of VO(2) 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 M(2) rather than M(1) 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. Nature Publishing Group 2016-12-16 /pmc/articles/PMC5159834/ /pubmed/27982066 http://dx.doi.org/10.1038/srep38514 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
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
title The nature of photoinduced phase transition and metastable states in vanadium dioxide
title_full The nature of photoinduced phase transition and metastable states in vanadium dioxide
title_fullStr The nature of photoinduced phase transition and metastable states in vanadium dioxide
title_full_unstemmed The nature of photoinduced phase transition and metastable states in vanadium dioxide
title_short The nature of photoinduced phase transition and metastable states in vanadium dioxide
title_sort nature of photoinduced phase transition and metastable states in vanadium dioxide
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5159834/
https://www.ncbi.nlm.nih.gov/pubmed/27982066
http://dx.doi.org/10.1038/srep38514
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