Limitations in cooling electrons using normal-metal-superconductor tunnel junctions

Jukka Pekola, Tero Heikkilä, Alexander Savin, J. T. Flyktman, F. Giazotto, F. W. J. Hekking

Research output: Contribution to journalArticleScientificpeer-review

93 Citations (Scopus)
164 Downloads (Pure)


We demonstrate both theoretically and experimentally two limiting factors in cooling electrons using biased tunnel junctions to extract heat from a normal metal into a superconductor. First, when the injection rate of electrons exceeds the internal relaxation rate in the metal to be cooled, the electrons do not obey the Fermi-Dirac distribution, and the concept of temperature cannot be applied as such. Second, at low bath temperatures, states within the gap induce anomalous heating and yield a theoretical limit of the achievable minimum temperature.
Original languageEnglish
Article number056804
Pages (from-to)1-4
Number of pages4
JournalPhysical Review Letters
Issue number5
Publication statusPublished - 6 Feb 2004
MoE publication typeA1 Journal article-refereed


  • cooling electron
  • superconductor
  • tunnel junction


Dive into the research topics of 'Limitations in cooling electrons using normal-metal-superconductor tunnel junctions'. Together they form a unique fingerprint.

Cite this