Dynamical photo-induced electronic properties of molecular junctions

TL;DR

This paper investigates the ultrafast photo-induced electronic behavior of molecular junctions using quantum transport simulations, revealing dynamical orbital reorganizations and states that could advance quantum nanodevice control.

Contribution

It provides new insights into the time-resolved charge dynamics and orbital reorganizations in molecular junctions under femtosecond laser pulses, highlighting phenomena like Rabi shifts and Floquet states.

Findings

Identification of dynamical Rabi shift in molecular orbitals

Observation of Floquet-like states induced by light

Analysis of light-molecule interaction effects on photocurrent

Abstract

Nanoscale molecular-electronic devices and machines are emerging as promising functional elements, naturally flexible and efficient, for next generation technologies. A deeper understanding of carrier dynamics in molecular junctions is expected to benefit many fields of nanoelectronics and power-devices. We determine time-resolved charge current flowing at donor- acceptor interface in molecular junctions connected to metallic electrodes by means of quantum transport simulations. The current is induced by the interaction of the donor with a Gaussian-shape femtosecond laser pulse. Effects of the molecular internal coupling, metal- molecule tunneling and light-donor coupling on photocurrent are discussed. We then examine the junction working through the time-resolved donor density of states. Non-equilibrium reorganization of hybridized molecular orbitals through the light-donor interaction gives rise to two phenomena: the dynamical Rabi shift and the appearance of Floquet-like states. Such insights into the dynamical photoelectronic structure of molecules are of strong interest for ultrafast spectroscopy, and open avenues toward the possibility of analyzing and controlling the internal properties of quantum nanodevices with pump-push photocurrent spectroscopy.