Semiconductor-To-Metal Transitions in Transition-Metal Compounds

The theory presented in a previous paper is applied to the transition-metal compounds which are known to exhibit semiconductor-to-metal transitions. In particular, the predictions of the theory are compared with the experimental results of Feinleib and Paul on ${\mathrm{V}}_2$ ${\mathrm{O}}_3$. Very good agreement is obtained for the magnitude of the energy gap and for its pressure and stress coefficients. The theory appears to be consistent with the available data on the other oxides of vanadium and titanium as well. Band models for all of these compounds are suggested. The effects of spin-disorder scattering and broadening, polaron formation, and non-stoichiometry are considered quantitatively.