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O: Oberflächenphysik

O 10: Semiconductor surfaces and interfaces

O 10.3: Talk

Monday, March 27, 2006, 15:30–15:45, PHY C213

In/Si(111): Chain structure and metal-insulator transition — •Andrey Stekolnikov, Jürgen Furthmüller, and Friedhelm Bechstedt — Friedrich-Schiller-Universität Jena, Institut für Festkörpertheorie und -optik, Max-Wien-Platz 1, D-07743 Jena

Atomic geometry and electronic structure of quasi-one-dimensional (1D) In/Si(111) systems with 4×1, 4×2, and 8×2 translational symmetries are studied by means of ab-initio calculations. While the 4×1 structure shows metallic behavior, the 4×2 (8×2) reconstruction leads to a pure semiconducting phase. For 4×2 (8×2) reduction of the total energy and formation of the energy gap are related to an additional bonding within the double In zig-zag chains. Simulated STM images show a good agreement with experimental ones. The geometry of In chains is very sensitive to all possible interactions. Several local minima may occur on the total-energy surface. The description of In-In and In-Si bonds plays an important role. The influence of the exchange and correlation within density functional theory calculations as well as In d-electrons is discussed in detail.