Single nuclear spin detection and control in a van der Waals material

TL;DR

This paper demonstrates the creation and control of single nuclear spins in hexagonal boron nitride, enabling atomic-scale NMR and advancing quantum sensing capabilities in two-dimensional materials.

Contribution

It introduces a method to create and identify specific spin defects in hBN, achieving high-fidelity nuclear spin control at room temperature.

Findings

Identified three defect types with hyperfine interactions.

Achieved coherent control with 99.75% fidelity.

Proposed chemical structures based on experiments and calculations.

Abstract

Optically active spin defects in solids are leading candidates for quantum sensing and quantum networking. Recently, single spin defects were discovered in hexagonal boron nitride (hBN), a layered van der Waals (vdW) material. Due to its two-dimensional structure, hBN allows spin defects to be positioned closer to target samples than in three-dimensional crystals, making it ideal for atomic-scale quantum sensing, including nuclear magnetic resonance (NMR) of single molecules. However, the chemical structures of these defects remain unknown, and detecting a single nuclear spin with an hBN spin defect has been elusive. In this study, we created single spin defects in hBN using $^{13}$C ion implantation and identified three distinct defect types based on hyperfine interactions. We observed both S=1 and S=1/2 spin states within a single hBN spin defect. We demonstrated atomic-scale NMR and coherent control of individual nuclear spins in a vdW material, with a $\pi$-gate fidelity up to 99.75% at room temperature. By comparing experimental results with density-functional theory calculations, we propose chemical structures for these spin defects. Our work advances the understanding of single spin defects in hBN and provides a pathway to enhance quantum sensing using hBN spin defects with nuclear spins as quantum memories.