Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 40: Transport: Molecular Electronics and Photonics (jointly with CPP, HL, MA, O)

TT 40.7: Vortrag

Mittwoch, 22. März 2017, 11:15–11:30, HSZ 201

Hierarchical Quantum Master Equation Approach to Vibrationally Coupled Nonequilibrium Charge Transport in Single-Molecule Junctions — •Christian Schinabeck¹, André Erpenbeck¹, Rainer Härtle², and Michael Thoss¹ — ¹Institut für Theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany. — ²Institut für Theoretische Physik, Georg-August-Universität Göttingen, Göttingen, Germany.

We investigate vibrationally coupled transport in single-molecule junctions using the hierarchical quantum master equation (HQME) approach [1-3]. This method allows a systematic convergence of the reduced dynamics of open quantum systems beyond the traditional perturbative master equations. We demonstrate the importance of vibrational nonequilibrium effects for a model molecular junction consisting of an electronic level coupled to fermionic leads as well as a vibrational mode. In particular, in the off-resonant transport regime, the inelastic cotunneling signal is analyzed for a vibrational mode in full nonequilibrium, revealing a complex interplay of different transport processes and deviations from the commonly used G₀/2 rule of thumb [3]. Moreover, an extension of the HQME approach is presented, which allows the calculation of the full counting statistics. Using this method, the influence of higher-order cotunneling processes on the current fluctuations is analyzed.

[1] Y. Tanimura et al., J. Phys. Soc. Jpn. 75, 082001 (2006).

[2] J. Jin et al., J. Chem. Phys. 128, 234703 (2008).

[3] C. Schinabeck et al., Phys. Rev. B 94, 201407 (2016).