Ab initio molecular dynamics study of the structural and electronic transition in VO₂

The temperature-induced structural and electronic transformation in VO₂ between the monoclinic M1 and tetragonal R phases was studied by ab initio molecular dynamics, based on the DFT+U scheme. We compare the structure of both phases, transition temperature and atomic fluctuations both above and below the transition, as well as the phonon density of states and scattering intensity of centroid position, with experimental data. The good quantitative agreement indicates that the chosen scheme provides a fairly good description of the energetics of the system. Analysis of the structural transformation was carried out by following the time evolution of dimerization amplitudes of V-atom chains and the twisting angle of V-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.

[1] D. Plašienka, R. Martonak, M. C. Newton, Phys. Rev. B 96, 054111 (2017)