Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Nanoelectronics III - Molecular Electronics
TT 6.5: Vortrag
Montag, 26. März 2007, 15:00–15:15, H19
Role of electronic structure in photo-assisted transport through atomic-sized contacts — •Janne Viljas1,2 and Juan Carlos Cuevas1,2,3 — 1Institut für Theoretische Festkörperphysik, Universität Karlsruhe, D-76128 Karlsruhe — 2Forschungszentrum Karlsruhe, Institut für Nanotechnologie, D-76021 Karlsruhe — 3Departamento de Física Teórica de la Materia Condensada C-V, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
We study theoretically quantum transport through laser-irradiated metallic atomic-sized contacts [1]. The radiation is treated classically, assuming its effect to be the generation of an ac voltage over the contact. We derive an expression for the dc current and compute the linear conductance in ideal one-atom thick contact geometries as a function of the ac frequency, concentrating on the role played by electronic structure. In particular, we present results for three metals (Al, Pt, and Au), the electronic structures of which are described with an spd tight-binding parametrization. Depending on the frequency and the metal, the ac voltage can either enhance or reduce the conductance. This can be intuitively understood in terms of the energy dependence of the transmission in the absence of radiation. Recent experiments [2] on laser-irradiated gold contacts support the view that photo-assisted processes may play an important role in the transport through such systems.
[1] J. K. Viljas and J. C. Cuevas, cond-mat/0607505.
[2] D. Guhr, D. Rettinger, J. Boneberg, A. Erbe, P. Leiderer, and E. Scheer, cond-mat/0612117 and this conference.