Laser-induced currents along molecular wire junctions

TL;DR

This paper investigates laser-induced electronic currents in molecular wires, focusing on how electron-vibrational interactions affect transport, and identifies two rectification mechanisms with the Stark effect being notably robust.

Contribution

It extends previous models to include vibrational effects in molecular wire transport under laser fields, revealing the robustness of Stark-effect-based rectification.

Findings

Stark effect-based rectification is highly efficient and robust.

Near-resonance photon absorption is fragile to vibrational decoherence.

Effective Schrödinger equation simplifies dynamics analysis.

Abstract

The treatment of the previous paper is extended to molecular wires. Specifically, the effect of electron-vibrational interactions on the electronic transport induced by femtosecond $\omega+2\omega$ laser fields along unbiased molecular nanojunctions is investigated. For this, the photoinduced vibronic dynamics of trans-polyacetylene oligomers coupled to macroscopic metallic leads is followed in a mean-field mixed quantum-classical approximation. A reduced description of the dynamics is obtained by introducing projective lead-molecule couplings and deriving an effective Schr\"odinger equation satisfied by the orbitals in the molecular region. Two possible rectification mechanisms are identified and investigated. The first one relies on near-resonance photon-absorption and is shown to be fragile to the ultrafast electronic decoherence processes introduced by the wire's vibrations. The second one employs the dynamic Stark effect and is demonstrated to be highly efficient and robust to electron-vibrational interactions.