Probing remote nuclear magnetic moments in hBN with VB− electron spin

Abstract

Since the initial discovery of optically addressable spins of the negatively charged boron vacancy defect (VB−) in hexagonal boron nitride (hBN), substantial progress has been made, enabling promising applications in quantum sensing, information processing, and simulations. A deep understanding of the VB− (electron): hBN (nuclear) spin systems is crucial for realizing these potentials. In this article, we employ electron nuclear double resonance to demonstrate the sensing of distant nuclear spins via the VB− electron spin. We identify the nature and localization of the probed nuclear magnetic moments as 14N spins localized ≈ 0.4 nm away from the vacancy and resolve the energies of the corresponding interactions. Density functional theory calculations further confirm these findings, providing a detailed description of the interactions between the VB− electron spin and surrounding nitrogen atoms in different shells. The results establish the VB− electron spin as a promising tool for developing van der Waals material-based nuclear magnetic resonance probes, advancing the understanding of spin physics in hBN, and unlocking its potential to study distant nuclear spin interactions in the host.