Phononic Crystal Superconducting Device Transition Width
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Solution Overview
Problem
Existing superconducting applications require cooling well below the transition temperature (Tc) to prevent resistive losses due to thermal phonon noise, leading to increased costs and time overhead, and a wide transition width that disrupts Cooper-pairs, limiting the quality factors and sensitivity of superconducting devices.
Innovation Solution
Engineering a phononic crystal with a periodic array of holes or plugs in a superconducting matrix material to create a phononic bandgap that suppresses decohering thermal phonon populations below the Cooper-frequency, thereby narrowing the superconducting transition width and reducing normal conduction electron populations near Tc.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling is performed well below Tc to prevent resistive losses, then reliability is improved, but temperature overhead and cost increase
Solution Approach 1:
The invention changes the phonon population parameter by introducing a phononic crystal structure with a bandgap at the Cooper frequency. This modifies the thermal phonon spectrum to suppress decohering phonons while maintaining superconductivity, allowing operation at higher temperatures closer to Tc without excessive resistive losses
Solution Approach 2:
The phononic crystal acts as an intermediary structure that mediates between the thermal environment and the superconducting electrons. By creating a phononic bandgap, it filters out harmful thermal phonons that would otherwise cause Cooper-pair breaking, enabling relaxed cooling requirements
2Stability of the object's composition
If cooling is performed well below Tc to suppress thermal phonon noise, then superconducting stability is improved, but time overhead and operational complexity increase
Solution Approach 1:
The phononic crystal structure is pre-engineered with a bandgap at the Cooper frequency before operation. This preliminary structural configuration proactively blocks harmful phonons from entering the superconducting region, eliminating the need for excessive cooling time to achieve stability
3Reliability
If phononic bandgap engineering is implemented to narrow transition width, then device performance is improved, but structural complexity increases
Solution Approach 1:
The phononic crystal is implemented as a periodic array of holes or posts that segments the superconducting material into unit cells. This segmentation creates the phononic bandgap effect while maintaining a relatively simple fabrication process using standard lithography and etching techniques
Solution Approach 2:
The invention creates a composite structure combining superconducting material with a phononic crystal pattern (air holes or different material posts). This composite approach achieves phonon engineering while using compatible materials and fabrication processes with existing superconducting device manufacturing
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
This approach allows for sharper superconducting transitions, relaxing cooling requirements, enhancing the quality factors and sensitivity of superconducting devices, and enabling higher performance in resonators, detectors, and transmission lines.
Implementation Method 1
the phononic crystal has a phononic bandgap at a frequency that suppresses a decohering thermal phonon population just below the Cooper-frequency of the matrix material
Implementation Method 2
a phononic crystal (PnC) can be used to engineer a phononic frequency gap that suppresses the decohering thermal phonon population just below the Cooper-frequency (fc)
Implementation Method 3
the holes or plug material provide an acoustic impedance mismatch with the matrix material
Implementation Method 4
suppressing the normal conduction electron population near Tc and narrowing the width of the superconducting transition
Data Source
AI summary
The invention is directed to a device and method to engineer the superconducting transition width by suppressing the phonon populations responsible for the Cooper-pair decoherence below the superconducting transition temperature via phononic bandgap engineering. The device uses phononic crystals to engineer a phononic frequency gap that suppresses the decohering thermal phonon population just below the Cooper-frequency, and thus the normal conduction electron population. For example, such engineering can relax the cooling requirements for a variety of circuits yielding higher operational quality factors for superconducting electronics and interconnects.