School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, United Kingdom.
Phys Rev Lett. 2010 Jul 30;105(5):056404. doi: 10.1103/PhysRevLett.105.056404.
Synchrotron x-ray total scattering studies of structural changes in rutile VO2 at the metal-insulator transition temperature of 340 K reveal that monoclinic and tetragonal phases of VO2 coexist in equilibrium, as expected for a first-order phase transition. No evidence for any distinct intermediate phase is seen. Unbiased local structure studies of the changes in V-V distances through the phase transition, using reverse Monte Carlo methods, support the idea of phase coexistence and point to the high degree of correlation in the dimerized low-temperature structure. No evidence for short-range V-V correlations that would be suggestive of local dimers is found in the metallic phase.
同步辐射 X 射线全散射研究显示，金红石相 VO2 在 340K 的金属-绝缘体相变温度下存在结构相变，其中单斜相和四方相处于平衡共存状态，符合一级相变的预期。没有发现任何明显的中间相存在的证据。通过反蒙特卡罗方法对相变过程中 V-V 距离的变化进行无偏局部结构研究，支持了相共存的观点，并指出了低温结构中二聚体的高度相关性。在金属相中没有发现与局部二聚体有关的短程 V-V 相关的证据。
