Modification of electron-phonon coupling by micromachining and suspension

Research output: Contribution to journalArticleScientificpeer-review


  • Olli Pentti Saira
  • Matthew H. Matheny
  • Libin Wang
  • Jukka Pekola
  • Michael Roukes

Research units

  • California Institute of Technology
  • Brookhaven National Laboratory


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 SiO 2 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.


Original languageEnglish
Article number024307
JournalJournal of Applied Physics
Issue number2
Publication statusPublished - 14 Jan 2020
MoE publication typeA1 Journal article-refereed

ID: 40886338