Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 27: II-VI semiconductors

HL 27.11: Vortrag

Mittwoch, 28. März 2007, 17:00–17:15, H13

Density of states and optical properties of MgO, ZnO and CdO — •André Schleife, Frank Fuchs, Claudia Rödl, and Friedhelm Bechstedt — Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany

In the last years ZnO attracted interest because of its potential application for optical devices. Alloys or heterostructures of ZnO with MgO and CdO or even magnetic materials (for spintronic applications) are discussed. From a theoretical point of view the (semicore) d-electrons are a challenging problem.

Employing first-principles calculations, the theoretical understanding has been pushed forward into two directions: First, using nonlocal functionals in the context of a generalized Kohn-Sham approach we obtain a DFT starting point which is more suitable for a perturbation-theory calculation of quasiparticle energies using the GW-approximation. This enables us to compute densities of states (DOS) from first principles which are in good agreement with experimental results. Second, ab initio optical spectra for the bulk have been calculated by solving the Bethe-Salpeter equation. This approach allows the investigation of bound states below the quasiparticle-gap as well as the computation of the dielectric function which is compared with measurements.

We present promising results and we are confident of being able to extend the application of this approach towards the parameter-free description of alloys or even heterostructures of these oxides.