Controllable Creation of Widely Dispersed Quantum Spin Sensors in Hexagonal Boron Nitride Using Ion Irradiation

The boron vacancy color-centers (BV) in hexagonal boron nitride (hBN), a van der Waals material, enable high-sensitivity optically detected magnetic resonance studies of magnetic dynamics. The BV is an atomic-scale, optically active, spin-1, quantum spin sensor (QSS) embedded in hBN where its proximity to an underlying sample in combination with its spin-dependent photoluminescence (PL), spin orientation homogeneity, and amenability to 2D stacking can enable sensitive detection of local static and dynamic magnetic fields in 2D vdW magnets. A primary challenge is controlling the density and uniformity of the QSSs created by ion irradiation performed by a commercially available focused ion beam instrument. We seek sparsely distributed QSSs to allow control over the number of QSSs being used for a particular measurement, but a detailed understanding of irradiation impact on the spatial distribution of the BVs remains elusive. We seek to better understand this through a combination of ion damage simulations available through the Stopping Range of Ions in Matter (SRIM) software and optical measurements of PL and magnetic resonance in BV ensembles to assess their areal density and uniformity and the impact of irradiation on the hBN. We report on methods for controlled QSS creation and our characterization of their uniformity and distribution through optically detected magnetic resonance and PL studies.