First-principles local-density-functional calculations are presented for the electronic band structures of the ordered vacancy defect chalcopyrites with formula $\mathrm{II}\ensuremath{-}{\mathrm{III}}_{2}\ensuremath{-}{\mathrm{VI}}_{4}$ for $\mathrm{II}=\mathrm{Zn},$ Cd, Hg, $\mathrm{III}=\mathrm{Al},$ Ga, In, and $\mathrm{VI}=\mathrm{S},$ Se, Te. Their relationship with the band structure of their parent chalcopyrite compounds $\mathrm{I}\ensuremath{-}\mathrm{III}\ensuremath{-}{\mathrm{VI}}_{2}$ with $\mathrm{I}=\mathrm{Cu},$ Ag, and their grand parent II-VI compounds is clarified. An empirical correction for the band gaps beyond local-density approximation is introduced and shown to give good agreement for cases where data are available. The chemical trends are discussed.

V. F. Parry

Papers

The Heat of Distillation of Coal