Phonon-mediated nonequilibrium interaction between nanoscale devices.

Area of Science:

• Condensed Matter Physics
• Mesoscopic Physics
• Quantum Electronics

Background:

• Two-dimensional electron systems (2DES) are fundamental in mesoscopic device research.
• Understanding interactions within 2DES is key to advancing quantum technologies.
• Phonon-mediated interactions can significantly impact electron behavior in confined systems.

Purpose of the Study:

• To investigate interactions between mesoscopic devices mediated by interface acoustic phonons.
• To explore the role of these interactions in the decoherence of quantum circuits.

Main Methods:

• Phonon spectroscopy was employed to study the interactions.
• Ballistic electrons from a quantum point contact emitted phonons, which were reabsorbed by a nearby 2DES.
• Energy spectroscopy using a tunable electrostatic barrier in a separate detector circuit analyzed excited electrons.

Main Results:

• The transferred energy was found to be limited by a maximum value.
• This maximum energy corresponds to Fermi-level electrons excited and backscattered by interface phonons.
• Evidence of phonon-mediated energy transfer between mesoscopic devices was observed.

Conclusions:

• Phonon-mediated interactions are significant in two-dimensional electron systems.
• These interactions play a critical role in the decoherence of solid-state-based quantum circuits.
• The findings provide insights into decoherence mechanisms relevant for quantum computing and electronics.