Modelling the enthalpy change and transition temperature dependence of the metal–insulator transition in pure and doped vanadium dioxide

Abstract

We compare various calculation methods to determine the electronic structures and energy differences of the phases of VO₂. We show that density functional methods in the form of GGA+U are able to describe the enthalpy difference (latent heat) between the rutile and M₁ phases of VO₂, and the effect of doping on the transition temperature and on the band gap of the M₁ phase. An enthalpy difference of ΔE₀ = −44.2 meV per formula unit, similar to the experimental value, is obtained if the randomly oriented spins of the paramagnetic rutile phase are treated by a non-collinear spin density functional calculation. The predicted change in the transition temperature of VO₂ for Ge, Si or Mg doping is calculated and is in good agreement with the experiment data.