High-temperature operation of a silicon qubit

Area of Science:

• Quantum Computing
• Materials Science
• Solid-State Physics

Background:

• Silicon (Si) qubits are crucial for quantum technologies due to long coherence times and silicon fabrication compatibility.
• Current Si qubit operation is limited to extremely low milli-Kelvin temperatures, hindering practical applications.
• Existing implementations often use gate-defined quantum dots or shallow impurities.

Purpose of the Study:

• To overcome the low-temperature operational constraint of silicon (Si) qubits.
• To explore the potential of deep impurities for enhanced qubit performance.
• To enable Si qubit operation at higher, more accessible temperatures.

Main Methods:

• Utilized single-electron tunneling transport to address a single deep impurity with strong electron confinement (up to 0.3 eV).
• Implemented deep impurities using tunnel field-effect transistors (TFETs) instead of conventional field-effect transistors (FETs).
• Achieved qubit operation via a spin-blockade effect based on tunneling transport through two impurities.

Main Results:

• Demonstrated successful qubit operation at elevated temperatures of 5-10 Kelvin.
• Showcased the effectiveness of deep impurities and TFETs in achieving higher operating temperatures.
• Established a method for qubit operation based on spin-blockade and tunneling transport.

Conclusions:

• This study significantly alleviates the low operating temperature limitation for silicon spin qubits.
• The developed approach using deep impurities in TFETs opens possibilities for quantum technology at higher temperatures.
• Further advancements in fabrication and control could lead to widespread adoption of silicon spin qubits in practical quantum devices.