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HL: Fachverband Halbleiterphysik

HL 40: ZnO: preparation and characterization III

HL 40.7: Vortrag

Donnerstag, 26. März 2009, 11:15–11:30, BEY 118

A comparative study of DFT corrections to charge transition levels of transition metals in ZnO — •Marc A. Gluba and N. H. Nickel — Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (formerly Hahn-Meitner-Institut Berlin), Kekuléstraße 5, D-12489 Berlin, Germany

Transition metals (TM) doped into zinc oxide (ZnO) have attracted considerable interest because of their potential application for spintronic devices. Since the experimental realization of dilute ferromagnetic ZnO is still challenging a detailed knowledge of the atomic structure and the energetics of TM ions in ZnO is essential. Density functional theory (DFT) is a feasible tool for the prediction of both, the local structure and stable charge states of single TM ions in a ZnO host matrix. However, since DFT is a ground state theory it shows significant deficiencies in describing the fundamental band gap especially of wide gap semiconductors like ZnO. Therefore, charge transition levels of dopands calculated by DFT have to be carefully interpreted. In this study we compare two different approaches for the correction of the fundamental band gap of ZnO – the a posteriori correction by Janotti and Van de Walle [Phys. Rev. B 76, 165202 (2007)] with an a priori approach by Paudel and Lambrecht [Phys. Rev. B 77, 205202 (2008)]. Hence we determine the corrected charge transition levels of common transition metals in ZnO.