Comparative study on the performance of exchange and correlation in wide-gap semiconductors: the case of BeS, BeSe, and BeTe

Abstract

The structural and elastic properties of Bechalcogenides belonging to zinc-blende group are computed using various flavors of exchange-correlation (XC) functionals. The present results are compared with respect to those of the common generalized-gradient approximation GGA-PBE. Based on AM05 functional, we find that the optimized lattice parameters corroborate well the experimental data. Using the self-consistent GW approximation, the quasiparticle band structures are calculated within the AM05 optimized structural parameters. In this respect, the results of the electronic excitations rely on an initial electronic structure determined through the hybrid XC functional. The values of band gap energies are adequately estimated. For comparison, the emerged hybrid functional HSE06 in conjunction with the self-consistent GW calculations is presented and this drives to amply adequate values for the band gaps. Moreover, it has been exhibited that the new MBJLDA approximation provides an excellent description for the energy gaps along C-X points with regards to GW results and experimental realizations.