Magnetic Field Sensitivity Optimization of Negatively Charged Boron Vacancy Defects in hBN.

Abstract

Optically active spin defects in hexagonal boron nitride (hBN) have recently emerged as compelling quantum sensors hosted by a two dimensional (2D) material. The photodynamics and sensitivity of spin defects are governed by their level structure and associated transition rates. These are, however, poorly understood for spin defects in hBN. Here, optical and microwave pump-probe measurements are used to characterize the relaxation dynamics of the negatively charged boron vacancy (VB−)—the most widely-studied spin defect in hBN. A 5-level model is used to deduce transition rates that give rise to spin-dependent VB− photoluminescence, and the lifetime of the VB− intersystem crossing metastable ..