# Coupling MOS Quantum Dot and Phosphorus Donor Qubit Systems

## TL;DR

This paper presents a novel MOS-based qubit system coupling a quantum dot with a phosphorus donor, demonstrating coherent two-axis control via tunable exchange and hyperfine interactions, advancing scalable quantum computing architectures.

## Contribution

Introduces a highly tunable MOS-compatible qubit design coupling a quantum dot with a phosphorus donor, enabling coherent two-axis control of two-electron spin qubits.

## Key findings

- First demonstration of coherent two-axis control in QD-donor qubits
- Electrical tuning of exchange and hyperfine interactions achieved
- Qubit decoherence primarily caused by charge noise

## Abstract

Si-MOS based QD qubits are attractive due to their similarity to the current semiconductor industry. We introduce a highly tunable MOS foundry compatible qubit design that couples an electrostatic quantum dot (QD) with an implanted donor. We show for the first time coherent two-axis control of a two-electron spin qubit that evolves under the QD-donor exchange interaction and the hyperfine interaction with the donor nucleus. The two interactions are tuned electrically with surface gate voltages to provide control of both qubit axes. Qubit decoherence is influenced by charge noise, which is of similar strength as epitaxial systems like GaAs and Si/SiGe.

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Source: https://tomesphere.com/paper/1705.05887