First-principles study of BNxSb1-x, BPxSb1-x, and BAsxSb1-x, alloys

摘要

The first ab initio calculations were carried out for the electronic, structural and thermodynamic properties of BNxSb1-x, BPxSb1-x and BAsxSb1-x boron ternary alloys. The full potential linearized augmented plane wave (FP-LAPW) method was employed within density functional theory (DFT). The local density approximation was used with generalized gradient correction (GGA) as well as the Engel-Vosko GGA formalism to calculate the band gap. The effect of composition on lattice constants, bulk modulus and band gap was investigated. Deviations of the lattice constants from Vegard's law and the bulk modulus from linear concentration dependence (LCD) were observed for the three alloys. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers. In addition, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing Delta H-m as well as the phase diagram. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.