Instituto de Ciencia de Materiales de Madrid
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Molecular wires acting as coherent quantum ratchets

Jörg Lehmann, Sigmund Kohler, Peter Hänggi, and Abraham Nitzan
Phys. Rev. Lett. 88, 228305 (2002)

The effect of laser fields on electron transport through a molecular wire 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 on 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.

[ICMM-CSIC] [Condensed Matter Theory]
last modified: 15.3.2024 by Sigmund Kohler