Semiconductor-Superconductor Hybrid Structure With Higher Critical Field

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Solution Overview

Problem

Existing semiconductor-superconductor hybrid devices are limited by a low critical field, which restricts their operation in strong magnetic fields, leading to a loss of superconducting behavior and potential poisoning of Majorana zero modes due to quasiparticles crossing the topological gap.

Innovation Solution

Incorporating a discontinuous portion of a non-ferromagnetic metal, such as platinum, into the superconductor component increases the critical field, allowing the device to operate in stronger magnetic fields and maintain superconductivity, thereby protecting Majorana zero modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a conventional superconductor component is used in the hybrid device, then the device structure is simple, but the critical field is low which limits operation in strong magnetic fields

Engineering Contradiction:

Improvedevice structureVSAvoidcritical field

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The superconductor component is constructed as a composite material system combining aluminum (continuous phase) with discontinuous portions of non-ferromagnetic metal such as platinum or gold. This composite structure increases the critical field from approximately 0.5-1 Tesla for pure aluminum to above 1 Tesla, enabling operation in stronger magnetic fields while maintaining superconductivity and protecting Majorana zero modes

Inventive Principle:

Principle #40Composite materials

2Reliability

If the critical field is increased by adding non-ferromagnetic metal, then the device can operate in stronger magnetic fields, but the superconductor component structure becomes more complex

Engineering Contradiction:

Improvecritical fieldVSAvoidsuperconductor component structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Rather than uniformly mixing metals throughout the superconductor, the invention introduces non-ferromagnetic metal only as discontinuous portions or localized regions within the aluminum matrix. This localized approach increases the critical field while minimizing structural complexity and maintaining the bulk superconducting properties of the aluminum component

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If a low critical field superconductor is used, then the fabrication process is simple, but the device loses superconductivity in strong magnetic fields causing quasiparticle poisoning

Engineering Contradiction:

Improvefabrication processVSAvoidquasiparticle poisoning

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The aluminum-based superconductor is enhanced with discontinuous portions of non-ferromagnetic metal to create a composite structure with elevated critical field. This modification enables the device to maintain superconductivity in strong magnetic fields (above 1 Tesla), preventing quasiparticles from crossing the topological gap and poisoning the Majorana zero modes, while remaining compatible with existing fabrication processes

Inventive Principle:

Principle #40Composite materials

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 inclusion of a non-ferromagnetic metal discontinuous portion enhances the critical field, enabling the device to withstand higher magnetic fields without losing superconductivity and providing better protection against quasiparticle poisoning, thus supporting more stable quantum computing operations.

Implementation Method 1

Dinner et al (arXiv:1011.4599v2 [cond-mat.supr-con]) discloses nanoscale pores in superconducting Nb films, which pores act as artificial flux pinning centres.

Methodology Applied

Scientific EffectFlux pinning:

Implementation Method 2

The device is cooled to a temperature where the superconductor (e.g. Aluminium, Al) exhibits superconducting behaviour.

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Implementation Method 3

Spin degeneracy can be lifted by means of a magnetic field, causing an energy level spilt between the differently spin-polarized electrons. This is known as the Zeeman effect.

Methodology Applied

Scientific EffectZeeman effect: Zeeman Effect

Data Source

PatentEP4111508B1Semiconductor-superconductor hybrid device and fabrication thereof

Publication Date: 2025.11.19 MICROSOFT TECHNOLOGY LICENSING LLC

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Figure 2b~3
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AI summary

A semiconductor-superconductor hybrid device comprises a semiconductor component and a superconductor component arranged over the semiconductor component, The superconductor component comprises a continuous portion of a superconductor material and a discontinuous portion of a non-ferromagnetic metal. The discontinuous portion is configured to increase the critical field of the superconductor component. It has been found that providing a superconductor component with a discontinuous portion of non-ferromagnetic metal may increase the critical field of the superconductor component, allowing the device to be operated in a stronger magnetic field. Further aspects provide a method of fabricating the device, and the use of a non-ferromagnetic metal to increase the critical field of a superconductor component of a semiconductor-superconductor hybrid device.