Vibrational effects in laser driven molecular wires

TL;DR

This paper investigates how vibrational modes in molecular wires affect laser-controlled electron transport, deriving a quantum kinetic model to analyze phenomena like ratchet currents and laser switching.

Contribution

It introduces a Hartree-Fock based quantum kinetic framework to study vibrational effects on laser-driven electron transport in molecular wires.

Findings

Vibrational modes induce effective electron-electron interactions.

Laser fields can generate ratchet or pump currents.

Laser switching of current is achievable in molecular wires.

Abstract

The influence of an electron-vibrational coupling on the laser control of electron transport through a molecular wire that is attached to several electronic leads is investigated. These molecular vibrational modes induce an effective electron-electron interaction. In the regime where the wire electrons couple weakly to both the external leads and the vibrational modes, we derive within a Hartree-Fock approximation a nonlinear set of quantum kinetic equations. The quantum kinetic theory is then used to evaluate the laser driven, time-averaged electron current through the wire-leads contacts. This novel formalism is applied to two archetypical situations in the presence of electron-vibrational effects, namely, (i) the generation of a ratchet or pump current in a symmetrical molecule by a harmonic mixing field and (ii) the laser switching of the current through the molecule.