Predicted band-gap pressure coefficients of all diamond and zinc-blende semiconductors: Chemical trends

We have studied systematically the chemical trends of the band-gap pressure coefficients of all group IV, III-V, and II-VI semiconductors using first-principles band-structure method. We have also calculated the individual {open_quotes}absolute{close_quotes} deformation potentials of the valence-band maximum (VBM) and conduction-band minimum (CBM). We find that (1) the volume deformation potentials of the {Gamma}{sub 6c} CBM are usually large and always negative, while (2) the volume deformation potentials of the {Gamma}{sub 8v} VBM state are usually small and negative for compounds containing occupied valence {ital d} state but positive for compounds without occupied valence {ital d} orbitals. Regarding the chemical trends of the band-gap pressure coefficients, we find that (3) a{sub p}{sup {Gamma}{minus}{Gamma}} decreases as the ionicity increases (e.g., from Ge{r_arrow}GaAs{r_arrow}ZnSe), (4) a{sub p}{sup {Gamma}{minus}{Gamma}} increases significantly as anion atomic number increases (e.g., from GaN{r_arrow}GaP{r_arrow}GaAs{r_arrow}GaSb), (5) a{sub p}{sup {Gamma}{minus}{Gamma}} decreases slightly as cation atomic number increases (e.g., from AlAs{r_arrow}GaAs{r_arrow}InAs), (6) the variation of a{sub p}{sup {Gamma}{minus}L} are relatively small and follow similar trends as a{sub p}{sup {Gamma}{minus}{Gamma}}, and (7) the magnitude of a{sub p}{sup {Gamma}{minus}X} are small and usually negative, but are sometimes slightly positive for compounds containing first-row elements. Our calculated chemical trends are explained in terms of the energymore » levels of the atomic valence orbitals and coupling between these orbital. In light of the above, we suggest that {open_quotes}empirical rule{close_quotes} of the pressure coefficients should be modified. {copyright} {ital 1999} {ital The American Physical Society}« less