Ab initio molecular dynamics study of the structural and electronic transition in VO

The temperature-induced structural and electronic transformation in VO2 between the monoclinic M1 and tetragonal rutile phases was studied by means of ab initio molecular dynamics (MD), based on density functional theory with Hubbard correction (DFT+U). Analysis of the dynamical processes associated with the structural transformation was carried out on the atomic scale by following the time evolution of dimerization amplitudes of vanadium atom chains and the twisting angle of vanadium dimers. The electronic transition was studied by tracing the changes in projected densities of states and their correlation with the evolution of the structural transformation. Our results reveal a strong interconnection between the structural and electronic transformations and show that they take place on the same time scale.