Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 35: Postersession Transport: Nanoelectronics, Quantum Coherence and Quantum Information, Fluctuations and Noise
TT 35.18: Poster
Mittwoch, 25. März 2009, 14:00–18:00, P1A
Laser excitation of atomic point contacts on silicon membranes — •Reimar Waitz1, Olivier Schecker1,2, and Elke Scheer1 — 1University of Konstanz, D-78457 Konstanz, Germany — 2IMEP-LAHC, MINATEC-INPG, F-38016 Grenoble, France
Light-induced conductance changes in metallic atomic-sized contacts in the tunneling and in the contact regime are studied. For this purpose, a new type of mechanically controlled break-junction (MCBJ) has been used [1].
MCBJs are made of a metallic wire with a suspended constriction. This constriction, forming a 100 nm wide bridge, can be elongated until having - just before breaking - a diameter of one atom. The elongation is achieved by stretching the substrate, consisting of a 340 nm thin crystalline silicon membrane, in contrast to MCBJs on bulk substrates, which use the bending of the substrate.
Compared to MCBJs on bulk substrates, this new type is advantageous for measuring the conductance of atomic point contacts under laser irradiation. Both the very low absorption and the low reflectivity of the membranes for visible light, make it possible to separate effects caused by the metal from effects caused by the substrate.
On our Poster we present results on light-induced reversible conductance changes of gold contacts. The dependence on intensity, wavelength and polarisation of the incident light has been investigated.
[1] R. Waitz, O. Schecker, and E. Scheer, Rev. Sci. Instrum. 79, 093901 (2008)