Coherent Electron-Phonon Coupling in Tailored Quantum Systems

TL;DR

This paper investigates electron-phonon interactions in nanostructures, revealing interference effects causing oscillations in quantum dot current, which diminish with temperature increase, highlighting the role of phonons in decoherence.

Contribution

It provides experimental evidence of interference effects in electron-phonon coupling within quantum dots, demonstrating material-dependent oscillations and their temperature dependence.

Findings

Oscillations in quantum dot current are observed and are more pronounced in nanowires.

Oscillations disappear at higher temperatures, confirming phonon-related interference.

Material differences influence the strength of electron-phonon coupling effects.

Abstract

The coupling between a two-level system and its environment leads to decoherence. Within the context of coherent manipulation of electronic or quasiparticle states in nanostructures, it is crucial to understand the sources of decoherence. Here, we study the effect of electron-phonon coupling in a graphene and an InAs nanowire double quantum dot. Our measurements reveal oscillations of the double quantum dot current periodic in energy detuning between the two levels. These periodic peaks are more pronounced in the nanowire than in graphene, and disappear when the temperature is increased. We attribute the oscillations to an interference effect between two alternative inelastic decay paths involving acoustic phonons present in these materials. This interpretation predicts the oscillations to wash out when temperature is increased, as observed experimentally.