Intrinsic high-fidelity spin polarization of charged vacancies in hexagonal boron nitride

Sangha Kim
Harvard University, Cambridge, Massachusetts, USA _______________________________________

The negatively charged boron vacancy defect (VB?) in hexagonal boron nitride (hBN) has emerged as a promising platform for quantum technologies, particularly quantum sensing and quantum simulation. As a spin defect in a 2D material, VB? can be optically initialized and read out at room temperature, has a well-characterized atomic structure, and benefits from deterministic generation methods. In this work, we investigate the polarization dynamics of VB? through a combination of experimental measurements and theoretical modeling. Using the semiclassical model we developed, we predict ground- and excited-state spin polarization exceeding 95%, surpassing other existing solid-state spin defects. Additionally, we incorporate the effects of nearby nuclear spins into our model by analyzing nuclear spin polarization dynamics near ground- and excited-state level anti-crossings (GSLAC and ESLAC). Our experimental results align closely with Lindbladian numerical simulations, validating our model and providing deeper insight into spin-environment interactions. Finally, we present efforts to enhance the performance of VB? defects by modifying their symmetry properties. 

arXiv:2406.11953 [quant-ph]

Email: sanghakim@g.harvard.edu