Electronic structure augmented spherical waves

The results of our band structure calculations for GaN crystals are based on the local-density approximation (LDA) treatment of electronic exchange and correlation [17-19] and on the augmented spherical wave (ASW) formalism [20] for the solution of the effective single-particle equations. For the calculations, the atomic sphere approximation (ASA) with a correction term is adopted. For valence electrons, we employ outermost s and p orbitals for each atom. The Madelung energy, which reflects the long-range electrostatic interactions in the system, is assumed to be restricted to a sum over monopoles. 

The augmented spherical-wave method of Williams et al. [1.20] appeared in 1979 and is an efficient computational scheme to calculate self-consistent electronic structures and ground-state properties of crystalline solids. According to its inventors it is a "direct descendant of the LMTO technique", and a comparison will show that the two methods are indeed very similar. 

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