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Published on: August 2, 2019
Electron and phonon cooling in a superconductor-normal-metal-superconductor tunnel junction
Sukumar Rajauria1, P S Luo, T Fournier
1Institut Néel, CNRS and Université Joseph Fourier, 25 Avenue des Martyrs, BP 166, 38042 Grenoble, France.
Abstract:
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.
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