Regular Article

Structural and optoelectronic properties of B_xAl_1-xSb ternary alloys: first principles calculations

Applied Materials Laboratory, Research Center (CFTE), Sidi Bel Abbès Djillali Liabes University, 22000 Sidi Bel-Abbès, Algeria

^a e-mail: mbenchehima@yahoo.fr

Received: 24 August 2016
Revised: 18 October 2016
Accepted: 9 February 2017
Published online: 31 March 2017

Abstract

In this paper, the full potential linearized augmented plane wave (FP-LAPW) formalism based on density functional theory (DFT) has been performed. To study the structural properties of B_xAl_1-xSb at different boron concentrations x (0 ≤ x ≤ 1), we have used the local density approximation (LDA) and the generalized gradient approximation of Wu and Cohen (GGA-WC). The phase stability of AlSb and BSb binary compounds in zinc-blend and rock salt phases has been investigated. The equilibrium lattice constant (a), bulk modulus (B) and pressure derivative of bulk modulus B′ have been evaluated in both phases. We observe a small deviation from the linear concentration dependence (LCD) of the lattice constant parameter, while an important deviation of bulk modulus from “LCD” has been remarked. We have compared the results obtained to the available theoretical and experimental data for the binaries. The optoelectronic properties of B_xAl_1-xSb are studied in the most stable determined phase. In addition to the “GGA-WC”, the GGA of Engel and Vosko, and the recent developed Tran-Blaha-modified Becke-Johnson (TB-mBJ) schemes were used to study the electronic properties of B_xAl_1-xSb ternary alloys. It is found that the band gap of B_xAl_1-xSb vary non-linearly with the boron concentrations, giving a negative deviation from Vegard’s law. In addition, the optical properties such as the dielectric function, complex refractive index, absorption coefficient, optical conductivity and absorption coefficient are discussed in detail.