Suleiman Aminat Oyiza, Mansouri Sabeur, Émond Nicolas, Le Drogoff Boris, Bégin Théophile, Margot Joëlle, Chaker Mohamed
Institut National de la Recherche Scientifique, Énergie Matériaux Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes, QC J3X 1S2 Canada.
Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA.
Sci Rep. 2021 Jan 15;11(1):1620. doi: 10.1038/s41598-020-79758-1.
Phase competition in transition metal oxides has attracted remarkable interest for fundamental aspects and technological applications. Here, we report a concurrent study of the phase transitions in undoped and Cr-doped VO[Formula: see text] thin films. The structural, morphological and electrical properties of our films are examined and the microstructural effect on the metal-insulator transition (MIT) are highlighted. We further present a distinctive approach for analyzing the Raman data of undoped and Cr-doped VO[Formula: see text] thin films as a function of temperature, which are quantitatively correlated to the electrical measurements of VO[Formula: see text] films to give an insight into the coupling between the structural phase transition (SPT) and the MIT. These data are also combined with reported EXAFS measurements and a connection between the Raman intensities and the mean Debye-Waller factors [Formula: see text] is established. We found that the temperature dependence of the [Formula: see text] as calculated from the Raman intensity retraces the temperature profile of the [Formula: see text] as obtained from the EXAFS data analysis. Our findings provide an evidence on the critical role of the thermal vibrational disorder in the VO[Formula: see text] phase transitions. Our study demonstrates that correlating Raman data with EXAFS analysis, the lattice and electronic structural dynamics can be probed.
过渡金属氧化物中的相竞争因其基础研究价值和技术应用而备受关注。在此，我们报告了对未掺杂和Cr掺杂的VO₂薄膜相变的同步研究。我们对薄膜的结构、形态和电学性质进行了研究，并强调了微观结构对金属-绝缘体转变（MIT）的影响。我们还提出了一种独特的方法来分析未掺杂和Cr掺杂的VO₂薄膜的拉曼数据随温度的变化，这些数据与VO₂薄膜的电学测量结果定量相关，从而深入了解结构相变（SPT）与MIT之间的耦合。这些数据还与已报道的扩展X射线吸收精细结构（EXAFS）测量结果相结合，并建立了拉曼强度与平均德拜-瓦勒因子之间的联系。我们发现，从拉曼强度计算得到的温度依赖性与从EXAFS数据分析得到的温度分布曲线相吻合。我们的研究结果为热振动无序在VO₂相变中的关键作用提供了证据。我们的研究表明，将拉曼数据与EXAFS分析相关联，可以探测晶格和电子结构动力学。
