First-Principles Study of Structural and Electronic Properties of GaNxAs1-X Alloys

Using first-principles total energy calculations, we have studied the structural and electronic properties of GaN_xAs_1-x alloys within density-functional theory (DFT) framework. The validity of Local density approximation (LDA) and generalized gradient approximation (GGA) has been demonstrated by the calculations of lattice parameters and band-gap bowing. The results show that LDA is relatively more suitable for calculations of GaNAs alloy. The lattice constant calculated decreases in line with vegard´s law in contrast to that the band gap has big composition-dependent bowing parameters. The effects of relaxed atoms and bonds have also been discussed. The relaxation contributes significantly to band-gap bowing.