Driven-dissipative charge transport in small networks: negative conductance and light-induced currents.*

Nanojunction experiments with single molecules or quantum dots placed between macroscopic leads allow the exploration of quantum transport at the nanoscale [1]. We model these systems adopting a Markovian open-quantum system approach to compute the current-voltage response of small-size networks of interacting two-level conducting sites that are coupled to leads, and radiative and non-radiative reservoirs [2]. We model the phenomenon of light-induced current, reported theoretically and experimentally. We validate our Markovian model by reproducing the experimental results on negative conductance [3] of single-molecule junctions with a two-site model in the absence of electromagnetic driving. We show that Coulomb blocking of current can be neglected with an external electromagnetic driving source and non-radiative decay. At zero bias voltage, the direction of the photocurrent induced by the electromagnetic driving source depends on the type of delocalized orbital. We also discuss the possibility of tuning electron transport in infrared cavities under vibrational strong coupling [4] and suggest experiments that can verify our predictions.

[1] M. Thoss, and F. Evers, J. Chem. Phys., 148, 030901 (2018).

[2] F. Recabal and F. Herrera, submitted (2022).

[3] M. L. Perrin, et al., Nat. Nanotechnol. 9, 830-834.  (2014).

[4] F. Herrera, and J. Owrutsky, J. Chem. Phys., 152, 100902 (2020).