Theoretical prediction of the structural, electronic, and thermal properties of Al1−xBxAs ternary alloys

Abstract

First-principles calculations are performed to study the structural, electronic, and thermal properties of the AlAs and BAs bulk materials and Al1−xBxAs ternary alloys using the full potential-linearized augmented plane wave method within the density functional theory. The structural properties are investigated using the Wu–Cohen generalized gradient approximation that is based on the optimization of total energy. For band structure calculations, both Wu–Cohen generalized gradient approximation and modified Becke-Johnson of the exchange-correlation energy and potential, respectively, are used. The dependence of the lattice constant, bulk modulus, and band gap on the composition x was analyzed. The lattice constant for Al1−xBxAs alloys exhibits a marginal deviation from the Vegard's law. A small deviation of the bulk modulus from linear concentration dependence was observed for these alloys. The composition dependence of the energy band gap was found to be highly nonlinear. Using the approach of Zunger and coworkers, the microscopic origins of the gap bowing were detailed and explained. The quasi-harmonic Debye model was used to determine the thermal properties of alloys up to 500K.