Electronic properties of pseudocubic IV-V compounds with 3:4 stoichiometry: Chemical trends

We perform first-principles calculations based on density functional theory and quasiparticle GW approximation to investigate the chemical trends in mechanical and electronic properties of twelve IV(3)V(4) compounds (IV = C, Si, Ge, and Sn; V = N, P, and As). Our results indicate that these compounds are semiconductors, with the exception of C(3)P(4) and C(3)As(4). While Ge(3)P(4) and Ge(3)As(4) appear to be semimetals within local density approximation, but are, in fact, semiconductors with indirect band gaps, as revealed by GW calculations. We propose an empirical formula of band gaps for IV(3)V(4) compounds that depends only on the nearest-neighbor distance and electronegativity difference. (C) 2010 Elsevier B. V. All rights reserved.