High-temperature operation of a silicon qubit

TL;DR

This paper demonstrates the operation of silicon spin qubits at temperatures as high as 10 K by using deep impurities and tunnel field-effect transistors, potentially broadening practical quantum technology applications.

Contribution

It introduces a novel method for operating silicon qubits at elevated temperatures using deep impurities and TFETs, overcoming previous low-temperature limitations.

Findings

Qubit operation achieved at 5-10 K via spin-blockade effect.

Deep impurity confinement energy up to 0.3 eV enhances thermal stability.

Use of TFETs enables new qubit implementation approaches.

Abstract

This study alleviates the low operating temperature constraint of Si qubits. A qubit is a key element for quantum sensors, memories, and computers. Electron spin in Si is a promising qubit, as it allows both long coherence times and potential compatibility with current silicon technology. Si qubits have been implemented using gate-defined quantum dots or shallow impurities. However, operation of Si qubits has been restricted to milli-Kelvin temperatures, thus limiting the application of the quantum technology. In this study, we addressed a single deep impurity, having strong electron confinement of up to 0.3 eV, using single-electron tunnelling transport. We also achieved qubit operation at 5-10 K through a spin-blockade effect based on the tunnelling transport via two impurities. The deep impurity was implemented by tunnel field-effect transistors (TFETs) instead of conventional FETs. With further improvement in fabrication and controllability, this work presents the possibility of operating silicon spin qubits at elevated temperatures.