Electronic Microrefrigerator Based on a Normal-Insulator-Superconductor Tunnel Junction

摘要: We present measurements on a novel electronic microrefrigerator that can cool conduction electrons significantly below the lattice temperature. A normal‐insulator‐superconductor tunnel junction is used to extract from normal metal electrode whose energy higher than Fermi energy. Electrons with an average equal are returned by superconducting contact. Consequently, high‐energy thermal excitations removed metal, thus cooling electrons. For temperatures 100 mK data be explained simple theory incorporating BCS density of states in and coupling between phonons. At lower our measurement suggests electron energies depart strongly equilibrium distribution.