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Formulation of charge transport in molecular junctions with time‐dependent molecule‐leads coupling operators
Author(s) -
Peskin Uri
Publication year - 2017
Publication title -
fortschritte der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.469
H-Index - 71
eISSN - 1521-3978
pISSN - 0015-8208
DOI - 10.1002/prop.201600048
Subject(s) - molecule , coupling (piping) , perturbation (astronomy) , unitary state , work (physics) , physics , time evolution , charge (physics) , chemical physics , field (mathematics) , kinetic energy , statistical physics , classical mechanics , quantum mechanics , materials science , mathematics , political science , law , metallurgy , pure mathematics
The problem of time‐dependent molecule‐leads coupling in single‐molecule junctions is acute for the structure, stability and functionality of these systems during non‐equilibrium transport. Time‐dependence of molecule‐lead coupling operators may rise when they are perturbed directly, or formally (indirectly), when time‐dependent perturbation to the molecule or to the leads are mapped onto the coupling operators by unitary transformations. In this work a reduced density matrix formulation is outlined for the study of transport in the presence of time‐dependent couplings. The formulation assumes weak molecule‐lead coupling, but accounts for many body interactions within the molecule, and for strong time‐dependent field. For band limited or periodic fields the formulation leads to kinetic equations which map the time‐dependent transport problem onto a static transport problem with multiple leads, thus providing convenient working equations as well as a useful tool for interpreting experiments on field driven single molecule junctions. Applications to concrete models are demonstrated.