Molecular Wires Acting as Coherent Quantum Ratchets
Abstract
The effect of laser fields on the electron transport through a molecular wire being weakly coupled to two leads is investigated. The molecular wire acts as a coherent quantum ratchet if the molecule is composed of periodically arranged, asymmetric chemical groups. This setup presents a quantum rectifier with a finite dc-response in the absence of a static bias. The nonlinear current is evaluated in closed form within the Floquet basis of the isolated, driven wire. The current response reveals multiple current reversals together with a nonlinear dependence (reflecting avoided quasi-energy crossings) on both, the amplitude and the frequency of the laser field. The current saturates for long wires at a nonzero value, while it may change sign upon decreasing its length.
Cite
@article{arxiv.cond-mat/0201480,
title = {Molecular Wires Acting as Coherent Quantum Ratchets},
author = {Jörg Lehmann and Sigmund Kohler and Peter Hänggi and Abraham Nitzan},
journal= {arXiv preprint arXiv:cond-mat/0201480},
year = {2009}
}
Comments
4 pages, 4 figures, RevTeX4