Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 36: TR: Poster Session

TT 36.18: Poster

Donnerstag, 25. März 2010, 14:00–18:00, Poster A

Nonequilibrium quantum transport in the local Holstein model — •Roland Hützen¹, Stephan Weiss², Michael Thorwart³, and Reinhold Egger¹ — ¹Heinrich-Heine Universität Düsseldorf — ²Niels Bohr Institute & Nano-Science Center, University of Copenhagen — ³FRIAS, Albert-Ludwigs Universität Freiburg

The local Holstein model serves as a basic model to study quantum transport through a single molecule. We employ the Keldysh path integral formalism to describe the system under nonequilibrium conditions. Free fermionic fields are integrated out and the coupling between the dot electron and the phonon mode is disentangled exactly by introducing auxiliary spin fields (S_j=0,± 1) on every Trotter slice. Those interact with each other over finite memory times, whereas free bosonic fields are integrated out as well. The remaining functional integration over the discrete spins is performed by means of the deterministic ISPI method [1]. We calculate the generating function for the tunneling current at finite bias voltages. For small electron-phonon coupling strengths λ we have checked our results against perturbation theory at finite temperature. In addition we have studied the regime of slow and fast phonon modes.

[1] S. Weiss, J. Eckel, M. Thorwart, and R. Egger, Phys. Rev. B 77, 195316 (2008).