Structural and electronic properties of chalcopyrite semiconductors AgXY2 (X = In, Ga; Y = S, Se, Te) under pressure

Results are presented of a first‐principles calculation of the direct band‐gap pressure coefficient ag for a series of Al, Ga and In chalcopyrite semiconductor compounds AgXY2 (X = Ga, In; Y = S, Se, Te) and the corresponding zinc‐blende structure. Good agreement was found between the calculated and experimental pressure coefficients. It was found that ag in chalcopyrites are dramatically reduced relative to zinc‐blende compounds, and that the Al → Ga → In substitution lowers ag in chalcopyrites more than in zinc‐blende compounds. As a result, the empirical rule suggested for zinc‐blende compounds, stating that for a given transition (e.g. Γ15v → Γ1c) ag does not depend on substitutions, has to be modified for chalcopyrites. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)