Ferromagnetic Contacts for Spin Qubit Initialization

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Solution Overview

Problem

Current methods for manipulating the spin state of electrons in quantum computing devices are inefficient in terms of energy consumption, lack control over spin state rotation, and suffer from magnetic cross-talk due to the need for external magnetic fields to set and read spin states in quantum wells.

Innovation Solution

The use of ferromagnetic contacts, particularly Heusler alloys, to initialize the spin state of electrons before they enter the quantum well, eliminating the need for external magnetic fields and reducing cross-talk by ensuring electrons are spin-polarized before entering the quantum well, thereby enhancing control and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external magnetic fields are used to set and read spin states in quantum wells, then spin state manipulation is achieved, but energy consumption increases and magnetic cross-talk occurs

Engineering Contradiction:

Improvespin state manipulation accuracyVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The ferromagnetic contact is used to pre-initialize the spin state of electrons before they enter the quantum well. This preliminary spin polarization eliminates the need for energy-consuming external magnetic fields during the quantum operation, as the electrons already possess the required spin state when injected into the quantum well

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts and eliminates the need for external magnetic field generation systems by implementing spin initialization at the contact level. The ferromagnetic contact inherently provides spin-polarized electrons through its magnetic properties, removing the separate magnetic field generation step that consumes energy and causes cross-talk

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If external magnetic fields are used to set and read spin states in quantum wells, then spin state manipulation is achieved, but magnetic cross-talk increases

Engineering Contradiction:

Improvespin state controlVSAvoidmagnetic cross-talk

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the external magnetic field generation step entirely by using ferromagnetic contacts that inherently provide spin-polarized electrons. This extraction of the magnetic field generation function eliminates the source of magnetic cross-talk while maintaining spin state control through contact-based spin initialization

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The ferromagnetic contact acts as an intermediary that transfers spin polarization directly to electrons through physical contact rather than through magnetic fields. This intermediary mechanism allows spin state control to be achieved through electrical contact and material properties rather than through magnetic field interaction, preventing cross-talk

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If ferromagnetic contacts are used to initialize spin states, then power consumption is reduced, but contact material compatibility must be ensured

Engineering Contradiction:

Improvepower consumptionVSAvoidcontact material compatibility

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent adjusts the composition parameters of Heusler alloy ferromagnetic contacts to match the lattice structure of underlying semiconductor materials. By changing the alloy composition ratios and crystallographic parameters, the contact material is made compatible with various semiconductor substrates, enabling low-power spin initialization without manufacturing difficulties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite Heusler alloy materials with specific compositional ratios to achieve both ferromagnetic properties and lattice matching with semiconductor substrates. These composite materials combine multiple elements in controlled proportions to simultaneously satisfy magnetic performance requirements and structural compatibility for ease of manufacture

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

This approach significantly reduces power consumption and magnetic cross-talk while improving the accuracy and reliability of spin state manipulation, ensuring electrons enter the quantum well with a predetermined spin state, thus enhancing the efficiency and precision of quantum computing operations.

Implementation Method 1

The use of ferromagnetic contacts, particularly Heusler alloys, to initialize the spin state of electrons before they enter the quantum well

Methodology Applied

Scientific EffectSpin polarization: Ferromagnetism

Data Source

PatentUS11264476B2Magnetic contacts for spin qubits

Publication Date: 2022.03.01 INTEL CORP

AI summary

Systems, apparatus, and methods for initializing spin qubits with no external magnetic fields are described. An apparatus for quantum computing includes a quantum well and a pair of contacts. At least one of the contacts is formed of a ferromagnetic material. One of the contacts in the pair of contacts interfaces with a semiconductor material at a first position adjacent to the quantum well and the other contact in the pair of contacts interfaces with the semiconductor material at a second position adjacent to the quantum well. The ferromagnetic material initializes an electron or hole with a spin state prior to injection into the quantum well.