Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 14: Transport: Nanoelectronics III - Molecular Electronics
TT 14.2: Vortrag
Dienstag, 26. Februar 2008, 09:45–10:00, H 3010
Effects of polaron hopping on the transport through DNA — •Benjamin B. Schmidt1,2, Matthias H. Hettler2, and Gerd Schön1,2 — 1Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany — 2Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Postfach 3640, 76021 Karlsruhe, Germany
Experiments probing the equilibrium transport in DNA [1] have led to the consensus that polaron hopping is the dominant transport mechanism of charge carriers in DNA. On the other hand in non-equilibrium experiments where short DNA molecules are connected to two biased leads various types of behaviour is seen (reaching from ballistic transport to insulating behaviour). The reason for this discrepancy is not resolved. We suggest that polaron hopping plays an important role in the non-equilibrium transport through DNA. Our theory is based on work by Böttger and Bryksin [2] on small polaron transport in bulk materials, which we extend to nanostructures where we also account for coupling of the DNA to the leads. It desribes the polaron hopping quantum mechanically by expanding the time evolution of the occupation number on the different bases along the Keldysh contour. We observe non-symmetric current-voltage characteristics which we relate to partial charge redistribution on the DNA due to the applied bias.
[1] P.Henderson et al., PNAS USA, 96, 8353 (1999)
[2] H. Böttger and V. V. Bryksin, ‘Hopping conduction in Solids’, Akademie Verlag Berlin, (1985)