Superconductor-Shunted NIS Cooler for Uniform Current Flow
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Solution Overview
Problem
Current NIS coolers have a limited temperature throw and suffer from severe overheating due to non-equilibrium quasi-particles in the superconducting leads, which leads to inefficiencies and heat generation.
Innovation Solution
Incorporating a superconductor shunt layer on the normal metal layers of NIS or NISN junctions to provide a lower resistance path for current flow, thereby reducing ohmic losses and promoting uniform current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current is run through the NIS cooler to improve cooling power, then cooling performance is enhanced, but severe overheating occurs in the superconducting electrodes due to non-equilibrium quasi-particles
Solution Approach 1:
The patent extracts the harmful non-equilibrium quasi-particles from the superconducting leads by introducing normal metal quasiparticle traps. These traps selectively remove excess quasi-particles that cause overheating, allowing high current to flow through the NIS junction for improved cooling power while preventing temperature buildup in the superconducting electrodes.
Solution Approach 2:
The patent introduces normal metal quasiparticle traps as intermediary elements between the NIS junction and the superconducting leads. These intermediary traps provide a controlled pathway for quasi-particle relaxation, mediating the interaction between high current flow and superconducting material to prevent overheating while maintaining cooling performance.
2Productivity
If normal metal is used in the NIS junction to enable electron tunneling, then cooling function is achieved, but I^2*R losses cause heat generation and reduce efficiency
Solution Approach 1:
The patent applies local quality by making only the specific regions where quasiparticle trapping is needed (the normal metal leads adjacent to the NIS junction) have normal metal properties, while the rest of the current path uses superconducting material. This localized approach reduces I^2*R losses in the bulk current path while maintaining the necessary electron tunneling function at the junction interface.
Solution Approach 2:
The patent creates a composite structure combining normal metal and superconducting materials in a hybrid NISN junction configuration. The normal metal portions provide quasiparticle trapping functionality, while the superconducting portions provide low-resistance current transport, achieving both cooling function and reduced energy losses through material composition optimization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The superconductor shunts effectively reduce I^2*R losses in the normal metal layers, enhance the temperature difference between the hot and cold sides, and mitigate heat generation due to nonuniform current flow.
Implementation Method 1
a superconductor shunt layer is disposed on the normal layer (N) of the NIS or both normal layers of NISN devices that forms the junctions
Implementation Method 2
The superconductor shunt layer shunts current from the normal metal layer by providing a lower resistance path
Implementation Method 3
Solid-state electron cooling by the tunneling of 'hot' electrons across a normal metal - insulator -superconductor (NIS) junction, using a bias voltage
Implementation Method 4
quasi-particles migrate to the normal metal and relax their energy there through electron-electron and electron-phonon interaction
Implementation Method 5
quasi-particles migrate to the normal metal and relax their energy there through electron-electron and electron-phonon interaction
Data Source
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AI summary
A solid state cooler device is disclosed that includes a first superconductor shunt, a first normal metal pad disposed on the first superconductor shunt, and a first insulator layer and a second insulator layer disposed on the normal metal pad and separated from one another by a gap. The solid state cooler device also includes a first superconductor pad disposed on the first insulator layer and a second superconductor pad disposed on the second insulator layer, a first conductive pad coupled to the first superconductor pad, and a second conductive pad coupled to the second superconductor pad. Hot electrons are removed from the first normal metal pad when a bias voltage is applied between the first conductive pad and the second conductive pad, wherein the first superconductor shunt facilitates even current distribution through the device.