PbSe vs. CdSe: Thermodynamic properties and pressure dependence of the band gap

Thermodynamic properties and band structure have been calculated for both PbSe and CdSe, using full-potential linear muffin-tin orbital (FP-LMTO) method and various energy functionals. Both local density approximation (LDA) and generalized gradient approximation (GGA) were used. It was found that LDA underestimates both band gap and lattice constant for PbSe, whereas GGA overestimates them. Opposite trends in band gap dependence upon pressure for PbSe and CdSe have been confirmed. Band gap pressure coefficients have been determined for both PbSe and CdSe. For PbSe, this coefficient is in relatively good agreement with other calculations and recent experiments.