Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 33: Transport - Nanoelectronics III: Molecular Electronics

TT 33.2: Vortrag

Dienstag, 8. März 2005, 14:15–14:30, TU H3027

Electrical transport through DNA molecules under stretching — •Ning Kang, Roman Lehner, Artur Erbe, and Elke Scheer — Department of Physics, University of Konstanz, Germany

Understanding the mechanism of electron motion along DNA is an essential step for the development of DNA-based molecular electronics. However, a number of contradicting findings were reported regarding the electronic properties of DNA. Theoretical calculations have demonstrated that the charge transport through the DNA will be strongly influenced by conformational transitions. To probe this effect, we have measured the resistance of DNA molecules under stretching with the help of the mechanically controllable break junction technique (MCB). Using the break junctions, we are able to fabricate electrodes with nanometer separation and fine-tune the tunneling gap between electrodes down to a resolution in the picometer range. In our experiments, we used 10-nm-long (30 base pairs) DNA with thiol groups at both ends, and stretched continuously the trapped molecules by means of MCB. A discrete two-level resistance switching behavior is observed when changing the distance of the electrodes, which might be related to a conformation transition of the DNA under stretching. To clarify whether the measured signal is from molecules, we also perform the measurements with a specific enzyme that cuts the DNA.