Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 103: Transport: Poster Session

TT 103.10: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster B

Light-induced changes of the electronic transport of atomic-sized contacts — •Matthias Bädicker, Daniel Benner, Golaleh Ghafoori, Johannes Boneberg, and Elke Scheer — Universität Konstanz, Germany

We investigate the influence of laser light onto the electrical transport of atomic sized Au contacts realized by the mechanically controllable break junction (MCBJ) technique. Experiments on MCBJs showed light-induced conductance changes, which have been interpreted as photo-assisted transport due to the excitation of high-energetic quasiparticles and collective effects such as surface plasmon excitation. Also optical near field enhancement caused by antenna effects as well as thermal expansion and thermo power may contribute to the signal [1-4]. The influence of surface plasmons is of particular interest for this work, because they provide a way to bring light to the contact without illuminating it directly. To excite and detect surface plasmons we fabricated grating couplers at either side of the constriction. Optical measurements carried out simultaneously with the transport measurements confirm the excitation and transmission of surface plasmons through the constriction [5,6]. In this work we concentrate on time-resolved transport experiments to distinguish between heating effects [7] and influences due to the electric field modulation of the plasmons.

[1] J.K. Viljas et al., PRB 75, 075406(2007).

[2] D. Guhr et al., PRL 99, 086801 (2007).

[3] N. Ittah et al., Nano Lett. 11, 2 (2011).

[4] Nano Lett. 9, 4 (2009).

[5] D. Benner et al., New J. Phys. 15 113014.

[6] Nano Lett., 14(9) (2014).

[7] A. Ganser et al., APL 105, 191119 (2014).