Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 38: Poster Session Transport

TT 38.11: Poster

Mittwoch, 16. März 2011, 14:00–18:00, P3

Laser induced electronic transport through metallic atomic-sized contacts — •Matthias Bädicker, Daniel Benner, Reimar Waitz, Johann Berres, Paul Leiderer, Johannes Boneberg, and Elke Scheer — Fachbereich Physik, Universität Konstanz

We investigate the influence of chopped laser light onto the electronic transport through a metallic point contact. It has been shown that there are several contributions to the laser induced effect like thermal expansion, plasmons and others. Here we concentrate on the thermal effects by varying the metal and the substrate material using correlation measurements of mechanical stress and optical excitation.

We use lithographically fabricated Mechanically Controllable Break-Junctions (MCBJs) operated at ambient conditions for fabricating atomic-size contacts and atomically-sharp tips of gold or platinum. The substrates we used are massive reflective and semi-transparent materials.

Detailed analysis of light-induced conductance changes has shown photo-assisted transport due to the excitation of high-energetic quasiparticles and collective effects such as surface plasmon excitation. We optimize the light-induced effects for the development of optoelectronic devices by studying systematically the effects on different metals (gold and platinum), wavelengths, position of the laser spot, and geometries (e.g. polarization of the laser light).