A Comparative Study of the Influence of the Local Density Approximation and the Generalized Gradient Approximation on the Calculated Properties of the III-Nitride (110) Surfaces

Abstract

ABSTRACTWe present a systematic theoretical study of several III-nitride (110) surfaces based on accurate parameter-free, self-consistent total energy and force calculations using the density functional theory, the local density approximation (LDA), as parametrized by Perdew and Zunger, and the generalized gradient approximation (GGA), as proposed by Perdew, Burke, and Ernzerhof, for the exchange-correlation term; we use the Full Potential Linear Augmented Plane Wave (FPLAPW) approach (WIEN-97 code) associated with the slab supercell model to simulate the (110) surface. We studied BN, AlN, GaN, InN and compared the theoretical results as related to the use of the LDA and the GGA. We conclude that although the results for both approximations are similar, differences in structural parameters may be as large as 10%.