Design of a novel on-chip electronic refrigerator based on a normal-insulator-superconductor tunnel junction
- Harvard Univ., Cambridge, MA (United States)
We present a design for a novel electronic refrigerator having a base temperature of about 18 mK when operating from a bath temperature as high as 1.5 K. This all-electronic refrigerator is a factor of 10{sup 4} smaller and lighter than dilution and adiabatic demagnetization refrigerators, and is compatible with conventional photolithographic fabrication. The refrigerator, based on the unique thermal transport properties of a normal-insulator-superconductor (NIS) tunnel function, preferentially removes electrons whose energy is higher than the Fermi energy from a normal metal. Electrons with an average energy equal to the Fermi energy are returned to the metal by a superconductor contact. Consequently, high energy thermal excitations are removed from the normal metal, thus cooling the electrons. In our configuration, the junction is deposited on a Si{sub 3}N{sub 4} membrane of submicron thickness that thermally isolates the normal electrode from the bath. As a result, both electrons and phonons in the metal are cooled below the bath temperature. We calculate a cooling power of 2 nW at 100 mK, and a base temperature of 18 mK for a refrigerator area of about 100X100{mu}m{sup 2}. Using 10{sup 5} such refrigerator circuits, the cooling power can be increased to 200 {mu}W.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 183418
- Report Number(s):
- CONF-950676-; ISSN 0022-2291; CNN: Grant NAGW-4170; TRN: 96:000732-0033
- Journal Information:
- Journal of Low Temperature Physics, Vol. 101, Issue 3-4; Conference: Symposium on quantum fluids and solids, Ithaca, NY (United States), 12-17 Jun 1995; Other Information: PBD: Nov 1995
- Country of Publication:
- United States
- Language:
- English
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