Ab initiocalculation of the electronic, structural, and dynamical properties of AlAs and CdTe

The scalar-relativistic version of an accurate first-principles full-potential self-consistent linearized muffin-tin-orbital (LMTO) method has been employed for describing the physical properties of the III-V and II-VI semiconducting compounds. Results for the two prototypes, AlAs and CdTe, are presented. The presently employed modified version of the LMTO method is quite fast and goes beyond the usual LMTO-atomic-sphere-approximation (ASA) method in the sense that it permits a completely general shape of the potential and the charge density. Also, in contrast to LMTO-ASA, the present method is capable of treating distorted lattice structures accurately. The calculated value of the lattice parameter is equal to the experimental value for the III-V compound AlAs and lies within 2.5% of the measured value for the II-VI compound CdTe. The computed density of states is quite close to the photoemission data available for CdTe. The calculated values of the bulk modulus and the elastic constants are in good agreement with the experimental data except for ${\mathit{C}}_{44}$ in CdTe. The values of the phonon frequencies at some symmetry points are also in close agreement with the experimental data wherever available. The present method is thus capable of predicting many physical properties of the polar semiconductors both qualitatively and quantitatively.