Effects of strain on the electronic structure of VO2

We present cluster-dynamic mean field theory DMFT continuous time quantum Monte Carlo method calculations based on a downfolded tight-binding model in order to study the electronic structure of vanadium dioxide VO2 both in the low-temperature M1 and high-temperature rutile phases. Motivated by the recent efforts directed toward tuning the physical properties of VO2 by depositing films on different supporting surfaces of different orientations, we performed calculations for different geometries for both phases. In order to investigate the effects of the different growing geometries we applied both contraction and expansion for the lattice parameter along the rutile c axis in the three-dimensional translationally invariant systems miming the real situation. Our main focus is to identify the mechanisms governing the formation of the gap characterizing the M1 phase and its dependence on strain. We found that the increase of the bandwidth with compression along the axis corresponding to the rutile c axis is more important than the Peierls bonding-antibonding splitting.