Existence of an Independent Phonon Bath in a Quantum Device

Laëtitia Pascal (1) , Aurélien Fay , Clemens Winkelmann (1) , Hervé Courtois (1)

1 NEEL - QuNES - Nano-Electronique Quantique et Spectroscopie

At low temperatures, the thermal wavelength of acoustic phonons in a metallic thin film on a substrate can widely exceed the film thickness. It is thus generally believed that a mesoscopic device operating at low temperature does not carry an individual phonon population. In this work, we provide direct experimental evidence for the thermal decoupling of phonons in a mesoscopic quantum device from its substrate phonon heat bath at a sub-Kelvin temperature. A simple heat balance model assuming an independent phonon bath following the usual electron-phonon and Kapitza coupling laws can account for all experimental observations.

Domaines: Supraconductivité [cond-mat.supr-con]

Laëtitia Pascal, Aurélien Fay, Clemens Winkelmann, Hervé Courtois. Existence of an Independent Phonon Bath in a Quantum Device. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2013, 88 (10), pp.100502(R). ⟨10.1103/PhysRevB.88.100502⟩. ⟨hal-00776663v3⟩