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Understanding the Nature of the Kinetic Process in a VO 2 Metal-Insulator Transition

2010; American Physical Society; Volume: 105; Issue: 22 Linguagem: Inglês

10.1103/physrevlett.105.226405

1092-0145

Tao Yao, Xiaodong Zhang, Zhihu Sun, Shoujie Liu, Yuanyuan Huang, Yi Xie, Changzheng Wu, Xun Yuan, Wenqing Zhang, Ziyu Wu, Guoqiang Pan, Fengchun Hu, Liang Wu, Qinghua Liu, Shiqiang Wei,

ZnO doping and properties

Understanding the kinetics during the metal-insulator transition process is crucial to sort out the underlying physical nature of electron-lattice interactions in correlated materials. Here, based on the temperature-dependent in situ x-ray absorption fine structure measurement and density-functional theory calculations, we have revealed that the monoclinic-to-tetragonal phase transition of ${\mathrm{VO}}_{2}$ near the critical temperature is characterized by a sharp decrease of the twisting angle $\ensuremath{\delta}$ of the nearest V--V coordination. The ${\mathrm{VO}}_{2}$ metallization occurs in the intermediate monocliniclike structure with a large twist of V--V pairs when the $\ensuremath{\delta}$ angle is smaller than 1.4\ifmmode^\circ\else\textdegree\fi{}. The correlation between structural kinetics and electronic structure points out that the structural rearrangement is a key factor to narrow the insulating band gap.