Tunable plexciton dynamics in electrically biased nanojunctions

Abstract

Strong coupling between resonantly coordinated plasmonic modes and excitonic states from quantum emitters or analogous two-level systems has led to the realization of pronounced plexciton dynamics. Here, we present and discuss an unconventional approach for this purpose by designing an electrically driven system composed of quantum dots (QDs) trapped in an opening region between two metallic electrodes. By conducting theoretical and numerical investigations, we quantitatively show that under specific bias, radiatively generated plasmons in the device efficiently couple to the excitonic states arisen from quantum emitters in the tunnel. This resulted in pronounced Rabi oscillations and splitting of the classical dipole mode emitted from the tunnel junctions. By computing the local density of states and electroluminescence spectra, we demonstrated the emission of light from the gated system and verified the fundamental parameters of the proposed unique architecture depending on the current flow at the barrier. By taking advantage of the local nature of the excited plasmons and varying the number of QDs in the tunnel, we precisely modeled the plexcitonic coupling and quantified the Rabi splitting of the fundamental resonances around ħΩ ≈ 200 meV. Possessing immense potential to be exploited in devising advanced technologies, we envision that the electrically driven plexciton dynamics brings on-chip ultrafast and ultradense instruments one step closer to reality.