Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Nanoelectronics III - Molecular Electronics
TT 6.3: Vortrag
Montag, 26. März 2007, 14:30–14:45, H19
Influence of vibrational modes on the electronic properties of DNA — •Benjamin Schmidt1,2, Matthias Hellter2, Gerd Schön1,2, Evgeni Starikov2, and Wolfgang Wenzel2 — 1Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany — 2Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Postfach 3640, 76021 Karlsruhe, Germany
We investigate the electron (hole) transport through short double-stranded DNA wires in which the electrons are strongly coupled to the specific vibrational modes (vibrons) of the DNA. We analyze the problem starting from a tight-binding model of DNA, with parameters derived from ab-initio calculations, and describe the dissipative transport by equation-of-motion techniques. For homogeneous DNA sequences like Poly- (Guanine-Cytosine) we find the transport to be quasi-ballistic with an effective density of states which is modified by the electron-vibron coupling. At low temperatures the linear conductance is strongly enhanced, but above the ‘semiconducting’ gap it is affected much less. In contrast, for inhomogeneous (‘natural’) sequences almost all states are strongly localized, and transport is dominated by dissipative processes. In this case, a non-local electron-vibron coupling influences the conductance in a qualitative and sequence-dependent way.