Jahn-Teller Effect for a Single Vacancy in Diamondlike Covalent Solids

Abstract

The static Jahn-Teller effect is studied for a monovacancy ${\mathrm{V}}^{+}$, ${\mathrm{V}}^0$, and ${\mathrm{V}}^{-}$ in diamondlike covalent solids by a new method which applies to the case of linear combinations of atomic orbitals (LCAO) as wave functions. In this "rigid LCAO model" the orbitals are assumed to follow the nuclei rigidly in the deformation. The formal calculation is almost identical to that of the usual treatment of the Jahn-Teller effect by the perturbation method. For the vacancy in diamond we use the electronic structure determined by Coulson and Kearsley in a molecular model. We obtain energy lowerings of the order of 0.1 eV and distortion amplitudes of about 0.05 Å. Finally we compare our results with the experimental data.