The influence of structural disorder and phonon on metal-to-insulator transition of VO ₂.

ABSTRACT: We used temperature-dependent x-ray absorption fine structure (XAFS) measurements to examine the local structural properties around vanadium atoms at the V K edge from VO₂ films. A direct comparison of the simultaneously-measured resistance and XAFS regarding the VO₂ films showed that the thermally-driven structural transition occurred prior to the resistance transition during a heating, while  this change simultaneously occured during a cooling. Extended-XAFS (EXAFS) analysis revealed significant increases of the Debye-Waller factors of the V-O and V-V pairs in the {111} direction of the R-phase VO₂ that are due to the phonons of the V-V arrays along the same direction in a metallic phase. The existance of a substantial amount of structural disorder on the

SUBMITTER: Hwang IH 

PROVIDER: S-EPMC5666023 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature