Ultrafast structural dynamics of VO2
Ultrafast structural dynamics of VO2
复制标题
VO2 的超快结构动力学
DOI：
10.1103/physrevb.96.075128
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发表时间：
2017
影响因子：
3.7
通讯作者：
F. Fernández
中科院分区：
文献类型：
--
作者：
S. Lysenko;Nardeep Kumar;A. Rúa;J. Figueroa;Junqiang Lu;F. Fernández
通过监测外延和非外延VO2薄膜中绝缘体到金属的相变，在不同的时间尺度上解决了声子和光声子在光致晶格转变中的不同贡献。应用超快角分辨光散射技术，研究了外延薄膜内部失配应变对亚皮秒相变动力学的显著影响。这种技术也允许观察结构缺陷在瞬态演化中的贡献。用金兹堡-朗道形式理论讨论了超快结构相变动力学。利用一组实验数据，我们重建了光激发VO2的热力学势，并提供了超快光诱导结构相变的现象学模型。
Distinct contribution of acoustic and optical phonons in light-induced lattice transformation was resolved at different time scales by monitoring the insulator-to-metal phase transition in epitaxial and nonepitaxial VO2 films. Applying the ultrafast angle-resolved light scattering technique we demonstrate a significant influence of internal misfit strain in epitaxial films on subpicosecond phase transition dynamics. This technique also allows for observing a contribution of structural defects in the evolution of the transient state. The ultrafast structural phase transition dynamics is discussed in terms of the Ginzburg-Landau formalism. Using a set of experimental data we reconstruct the thermodynamic potential of photoexcited VO2 and provide a phenomenological model of the ultrafast light-induced structural phase transition.