1.
Phys Rev Lett
; 99(4): 047004, 2007 Jul 27.
Artigo
em Inglês
| MEDLINE
| ID: mdl-17678393
RESUMO
We present evidence for the cooling of normal-metal phonons, in addition to the well-known electron cooling, by electron tunneling in a superconductor-normal-metal-superconductor tunnel junction. The normal-metal electron temperature is extracted by comparing the device current-voltage characteristics to the theoretical prediction. We use a quantitative model for the heat transfer that includes the electron-phonon coupling in the normal metal and the Kapitza resistance between the substrate and the metal. It gives a very good fit to the data and enables us to extract an effective phonon temperature in the normal metal.