Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 75: Poster Session: Transport 1
TT 75.22: Poster
Donnerstag, 23. März 2017, 15:00–19:00, P2-EG
Comparison of dephasing models for molecular wires — •Patrick Karasch1, Verena Gupta1, Gabriele Penazzi1, Alessandro Pecchia2, Dmitry A. Ryndyk1, and Thomas Frauenheim1 — 1Bremen Center for Computational Materials Science, Universität Bremen, Germany — 2CNR-ISMN, Roma, Italy
In this work, we investigate the decoherence effects which play an important role in the charge transport characteristics of quantum wires at room temperature. For molecular junctions and onedimensional molecular wires we investigate the distinct dephasing models to calculate and compare the effective resistances and investigate the crossover from coherent Landauer transport to ohmic behavior in long wires. First, we consider the Momentum Relaxing Dephasing (MRD) and the Büttiker Probe (BP) models. These approaches rely on the empirical coupling strength of electronic states to the environment. Then we introduce the electron-phonon dephasing model and consider different approximations including the first Born approximation (BA) and the self-consistent Born approximation (SCBA). Besides, we consider the interplay of disorder and dissipation. Our theoretical method is based on the nonequilibrium Green function approach to quantum transport. To go towards the atomistic ab initio theory, we implemented the method in combination with the density functional based tight binding (DFTB) theory [1] within the DFTB+ code and DFTB-NEGF transport method.
[1] G. Penazzi et al., J. Phys. Chem. C 120, 16383 (2016)