Strain dependence of bonding and hybridization across the   metal-insulator transition of VO2
  Soft x-ray spectroscopy is used to investigate the strain dependence of the metal-insulator transition of VO2. Changes in the strength of the V 3d - O 2p hybridization are observed across the transition, and are linked to the structural distortion. Furthermore, although the V-V dimerization is well-described by dynamical mean-field theory, the V-O hybridization is found to have an unexpectedly strong dependence on strain that is not predicted by band theory, emphasizing the relevance of the O ion to the physics of VO2. 
J. Laverock, L. F. J. Piper, A. R. H. Preston, B. Chen, J. McNulty, K.   E. Smith, S. Kittiwatanakul, J. W. Lu, S. A. Wolf, ...
cond-mat.str-el cond-mat.mtrl-sci