Berlin 2005 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 5: Optische, metallische und magnetische Schichten

DS 5.4: Vortrag

Freitag, 4. März 2005, 11:30–11:45, TU HS110

Optical properties of ultrathin gold films — •Tobby Brandt, Natalia Drichko, Bruno Gompf, and Martin Dressel — 1. Physikalisches Institut der Universität Stuttgart

Ultrathin metal films (UTMF) serve as model systems for the insulator/metal transition in two dimensions. While the optical conductivity of thick metal films has been studied extensively, there are nearly no studies in the infrared and far-infrared region. Beside the fundamental question whether there exists a true metallic state at very low temperatures in 2-D-systemes at all, UTMFs show additional relaxation mechanisms due to electron-interface scattering and an changed electron structure due to electron confinement. To illuminate the conduction properties of UTMFs temperature and frequency dependent measurements are necessary. Optical properties of ultrathin Au films (<50Å) condensed on reconstructed Si(111)(7x7) surfaces have been measured in transmission and reflection between 400 cm⁻¹ and 5000 cm⁻¹ in situ in the temperature range between 5 K and room temperature. The development of the sheet resistance and conductivity of UTMFs is a function of film thickness will be discussed.