THE STRUCTURAL AND ELECTRONIC PROPERTIES OF BNxAs1-x ALLOYS

Abstract

The structural and electronic properties of BN x As 1-x alloys have been investigated in the total range of nitrogen by the FP-LAPW method based on DFT within the EV-PW-GGA scheme. The equilibrium lattice constants, bulk moduli, first-order pressure derivatives of the bulk moduli, and cohesive energies have been obtained by total energy calculations of the alloys after both volume and geometry optimizations. The large bowing parameters found for the lattice constants and bulk moduli have demonstrated that the validity of Vegard's linear rule in the definitions of these structural features of the BN x As 1-x alloys is broken. The energy bands and the effective masses of the alloys have been calculated as a function of nitrogen concentration. The large bowing displayed by the variation of the energy gaps has indicated the band gap engineering capacity of the BN x As 1-x alloys and again in deviations from Vegard's linear rule. The effective electron masses calculated either at the edges of the conduction bands or along the directions approaching the edges of the conduction bands are all found to be small with respect to the effective electron masses in the BAs and BN compounds calculated at the Δ min and X points, respectively.