Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)

O 59.114: Poster

Wednesday, March 24, 2010, 17:45–20:30, Poster B1

Influence of the XC Functional on Band Parameters of AlN, GaN and InN — •Luiz Claudio de Carvalho, Andre Schleife, Frank Fuchs, and Friedhelm Bechstedt — Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany

The group III-nitrides have a great potential for optoelectronic devices operating in the visible spectrum and deep ultraviolet. Therefore, a detailed knowledge of their structural, electronic and optical parameters is necessary for the interpretation of experimental data and theoretical results. The most successful theoretical method is the DFT, but its accuracy depends on the choice of the functional of the exchange-correlation (XC) energy. Different choices yield slightly varying results for the structural properties. However, this effect is usually believed to be small, when comparing the results of ab-initio calculations using different XC functionals. In this work we investigate the influence of the structural deviations, introduced by different XC functionals, on the quasiparticle-band structure. We present our results for AlN, GaN, and InN, comparing the XC functionals LDA, PBE, and AM05. DFT as implemented in the VASP code is used to calculate the lattice constants, bulk moduli, band-gap energies, volume deformation potentials and hydrostatic pressure coefficients. The quasiparticle band structures are obtained by GW calculations, using the hybrid XC functional HSE03 as a starting point. We compare our results with experimental data reported in the literature, and discuss the influence of the XC induced structural changes on the band parameters.