Superconductor junction for a solid state cooler

A cooler device comprising:

• a pair of normal metal-insulator-superconductor-superconductor-normal metal (NIS1S2N) junctions, each NIS1S2N junction comprising:
• a normal metal layer having a first side and a second side;
• an insulating layer overlying the second side of the normal metal layer;
• a first superconductor layer formed of a first superconductor material, the first superconductor layer having a first side overlying a side of the insulating layer opposite the side that overlies the normal metal layer;
• a second superconductor layer formed of a second superconductor material, the second superconductor layer having a first side overlying a side of the first superconductor material opposite the side that overlies the insulating layer, the second superconductor material has a higher diffusion coefficient than the first superconductor material and/or the second superconductor material has a lower recombination coefficient than the first superconductor layer, wherein the first superconductor layer has a thickness of about 1 coherence length to about 3 coherence lengths associated with the first superconductor material and the second superconductor layer has a thickness of at least 4 coherence lengths associated with the second superconductor material;
• and
• a normal metal layer quasiparticle trap coupled to a second side of the second superconductor layer via a normal metal bump bond;
• and
• wherein a bias voltage applied between the normal metal layer quasiparticle trap of a first NIS1S2N junction of the pair of NIS1S2N junctions and the normal metal layer quasiparticle trap of a second NIS1S2N junction of the pair of NIS1S2N junctions causes hot electrons to be removed from the normal metal layer through the insulating layer of the second NIS1S2N junction, the first superconductor layer of the second NIS1S2N junction, the second superconductor layer of the second NIS1S2N junction to the normal metal layer quasiparticle trap of the second NIS1S2N junction.

A method of forming a superconductor junction, the method comprising:

• providing a normal metal layer having a first side and a second side;
• disposing an insulating layer over the second side of the normal metal layer;
• disposing a first superconductor layer formed of a first superconductor material with a first side over a side of the insulating layer opposite the side that overlies the normal metal layer;
• disposing a second superconductor layer formed of a second superconductor material with a first side over a side of the first superconductor layer opposite the side that overlies the insulating layer, the second superconductor material has a higher diffusion coefficient than the first superconductor material and/or the second superconductor material has a lower recombination coefficient than the first superconductor layer, wherein the first superconductor layer has a thickness of about 1 coherence length to about 3 coherence lengths associated with the first superconductor material and the second superconductor layer has a thickness of at least 4 coherence lengths associated with the second superconductor material;
• and
• coupling a normal metal layer quasiparticle trap to a second side of the second superconductor layer with or without a normal metal bump bond.