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O: Oberflächenphysik

O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)

O 24.51: Poster

Wednesday, March 26, 2003, 14:30–17:30, P1

Clean and hydrogen-terminated GaP(001) surface structures calculated from first principles — •Patrick Hahn^1,2, Wolf G. Schmidt¹, Friedhelm Bechstedt¹, Olivia Pulci², and Rodolfo Del Sole² — ¹Institut für Festkörpertheorie und Theoretische Optik, Friedrich-Schiller-Universität Jena — ²Dipartimento di Fisica, Universita degli Studi di Roma Tor Vergata

We present first-principles calculations on the structural, electronic and optical properties of clean and hydrogen-exposed GaP(001) surfaces. For the clean GaP surface we predict a novel (2×4) surface structure, which combines anion-cation heterodimers and cation dimers. According to the calculations, this previously not discussed structure is stable for a wide range of surface preparation conditions. The GaP surface structure changes drastically if the sample is exposed to hydrogen. A particular stable structure consists of a phosphorous monolayer, with every second P atom hydrogen saturated. In conjunction with the available experimental data, our results indicate that hydrogen induces a longe-range order on the GaP(001) surface.