6533b854fe1ef96bd12ae048

RESEARCH PRODUCT

Direct measurement of the electron‐phonon relaxation rate in thin copper films

Ilari MaasiltaJani KiviojaJ. T. KarvonenL. J. Taskinen

subject

PhysicsCondensed Matter - Mesoscale and Nanoscale PhysicsCondensed matter physicsCondensed Matter - SuperconductivityFOS: Physical scienceschemistry.chemical_element02 engineering and technologyElectron021001 nanoscience & nanotechnology01 natural sciencesCopperSuperconductivity (cond-mat.supr-con)chemistryTunnel junctionScattering rateMesoscale and Nanoscale Physics (cond-mat.mes-hall)0103 physical sciencesElectron temperature010306 general physics0210 nano-technologyJoule heatingFermi gasOverheating (electricity)

description

We have used normal metal-insulator-superconductor (NIS) tunnel junction pairs, known as SINIS structures, for ultrasensitive thermometry at sub-Kelvin temperatures. With the help of these thermometers, we have developed an ac-technique to measure the electron-phonon (e-p) scattering rate directly, without any other material or geometry dependent parameters, based on overheating the electron gas. The technique is based on Joule heating the electrons in the frequency range DC-10 MHz, and measuring the electron temperature in DC. Because of the nonlinearity of the electron-phonon coupling with respect to temperature, even the DC response will be affected, when the heating frequency reaches the natural cut-off determined by the e-p scattering rate. Results on thin Cu films show a $T^{4}$ behavior for the scattering rate, in agreement with indirect measurement of similar samples and numerical modeling of the non-linear response.

yearjournalcountryeditionlanguage
2004-10-12physica status solidi (c)
https://doi.org/10.1002/pssc.200405307