Laser-induced currents along molecular wire junctions

摘要

The treatment of the previous paper is extended to molecular wires.Specifically, the effect of electron-vibrational interactions on the electronictransport induced by femtosecond $\omega+2\omega$ laser fields along unbiasedmolecular nanojunctions is investigated. For this, the photoinduced vibronicdynamics of trans-polyacetylene oligomers coupled to macroscopic metallic leadsis followed in a mean-field mixed quantum-classical approximation. A reduceddescription of the dynamics is obtained by introducing projective lead-moleculecouplings and deriving an effective Schr\"odinger equation satisfied by theorbitals in the molecular region. Two possible rectification mechanisms areidentified and investigated. The first one relies on near-resonancephoton-absorption and is shown to be fragile to the ultrafast electronicdecoherence processes introduced by the wire's vibrations. The second oneemploys the dynamic Stark effect and is demonstrated to be highly efficient androbust to electron-vibrational interactions.