Modification of electron-phonon coupling by micromachining and suspension
Abstract
Weak electron-phonon interaction in metals at low temperatures forms the basis of operation for cryogenic hot-electron bolometers and calorimeters. Here, we develop a thermometry scheme based on proximity supercurrent to study the thermal response of a thin gold film on a SiO2 platform at temperatures below 100 mK. We find that the exponent of the power law describing electron-phonon coupling in the film drops by approximately 1/2 as the platform is micromachined and released from its substrate. This contrasts the conventional theory for bulklike geometries that predicts integer-valued exponents. We attribute the fractional change to a modified phonon spectrum described by recent theoretical developments.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 14, 2020
- Source ID
- 10.1063/1.5132948
Entities
People
- Jukka Pekola
- Libin Wang
- Matthew Matheny
- Michael Roukes
- O.-P. Saira
Organizations
- Aalto University
- Army Research Office
- California Institute of Technology
- Research Council of Finland