First-principle study of structural, electronic and elastic properties of beryllium chalcogenides BeS, BeSe and BeTe

First-principles calculations have been used to investigated the structural, electronic and elastic properties of beryllium chalcogenides BeS, BeSe and BeTe, using the full-potential linear muffin-tin orbital (FP-LMTO) method. The exchange correlation energy is described in the local density approximation (LDA) using the Perdew-Wang parameterisation. From the results of the electronic properties, we find that these materials have indirect bandgaps. The structural parameters and the transition pressure from zinc-blende (B3) to the NiAs (B8) phase are determined. An agreement was found between our results and those of other theoretical calculations and the experimental data. A special interest has been made to the determination of the elastic constants since there have been no available experimental data. The calculated elastic constants found for BeS, BeSe and BeTe are C11 = 1.4032, 1.1311, 0.8556 Mbar, C12 = 0.9592, 0.7736, 0.5994 Mbar, C44 = 0.2389, 0.1938, 0.136 Mbar, respectively. These results compared to other theoretical work show a discrepancy which is due to the use of LDA.