Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 38: Poster Session Transport

TT 38.13: Poster

Mittwoch, 16. März 2011, 14:00–18:00, P3

Higher-order perturbation theory applied to time-dependent electron transport processes — •Bogdan Popescu and Ulrich Kleinekathöfer — Jacobs University Bremen, Germany

In the present work, the electron transport through a quantum system, modelled as a linear chain of tight-binding sites and coupled to external fermionic leads, is investigated using a reduced density matrix formalism [1]. This model may be applied to characterize a molecular wire or consecutive quantum dots coupled in series. The dynamics of the electrons tunnelling through the system is described by a quantum master equation derived in the framework of perturbation theory. The influence of higher-order terms [2] in the coupling to the leads has been investigated, i.e., the limits of the second-order perturbation theory have been shown. The present method is suitable to accurately describe stronger system-lead coupling. Additionally, this approach is able to accurately account for time-dependent effects of an external electric or magnetic field.
[1] S. Welack, M. Schreiber and U. Kleinekathöfer, J. Chem. Phys. 124, 044712 (2006).
J. Jin, X. Zheng and Y. Yan, J. Chem. Phys. 128, 234703 (2008).