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TT: Fachverband Tiefe Temperaturen

TT 6: Nanoelectronics III - Molecular Electronics

TT 6.4: Talk

Monday, March 26, 2007, 14:45–15:00, H19

Influence of chopped laser light onto the electronic transport through atomic-sized contacts — •Daniel Guhr, Dennis Rettinger, Johannes Boneberg, Artur Erbe, Paul Leiderer, and Elke Scheer — University of Konstanz, Germany

In our experiment we investigate the influence of laser irradiation onto the electrical conductance of gold nanocontacts established with the mechanically controllable breakjunction technique. We concentrate on the study of reversible conductance changes which can be as high as 200%. In our measurements we have varied the intensity, the polarisation and the wavelength of the laser beam in the visible range of the spectrum as well as its position on the sample. Under most conditions an enhancement of conductance is observed. We discuss several physical mechanisms which might contribute to the observed effect including thermal expansion, rectification of nonlinear current-voltage characteristics by the ac electric field of the laser light [1] and photon-assisted transport (PAT) [2]. From the analysis of our data we conclude that PAT is the dominating effect in out experiment while small contributions from thermal expansion cannot be excluded [3].

[1] R. Möller,J. Vac. Sci. Technol. B9, 506-509, 1991

[2] J.K. Viljas and J.C. Cuevas, cond-mat/0607505

[3] D. Guhr et al., cond-mat/0612117