Regensburg 2002 – wissenschaftliches Programm
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SYQT: Quantentransport auf molekularen Skalen
SYQT 1: Quantentransport auf molekularen Skalen
SYQT 1.5: Vortrag
Montag, 11. März 2002, 12:30–12:45, H2
Screening effects in molecular wires — •Stéphane Pleutin1, Hermann Grabert1, and Gert-Ludwig Ingold2 — 1Fakultät für Physik, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg — 2Institut für Physik, Universität Augsburg, Universitätsstr. 1, D-86159 Augsburg
We consider a molecular wire between two metallic planes in the limit of weak contacts. The molecule is modelled by a linear tight-binding chain and the π-electrons responsible for electrical conduction are described by Gaussian wave functions. Screening effects are included within the Hartree approximation using the Coulomb potential with image charges due to the electrodes.
We focus on the behaviour of the on-site potential, with or without electric field, within the molecular wire. The control parameters of the problem are the distance between the electrodes and the molecule, the radial spatial extension of the π-electrons, the length of the wire, the position of the Fermi level of the electrodes, and the temperature. In particular, we will point out the need to treat the molecular wire as a real 3D system, at least, as far as the screening effects are concerned. The results are compared with earlier studies [1,2]. Finally, we address transport properties of this system by using the Landauer formalism.
[1] W. Tian, S. Datta, S. Hong, R. Reifenberger, J.I. Henderson, and C.P. Kubiak, J. Chem. Phys. 109, 2874 (1998)
[2] V. Mujica, A.E. Roitberg, and M. Ratner, J. Chem. Phys. 112, 6834 (2000)