Lee W, Liu V S, Zhang Z, Kim S, Gong R, Du X, Pham K, Poirier T, Hao Z, Edgar J H, Kim P, Zu C, Davis E J, Yao N Y
Harvard University, Department of Physics, Cambridge, Massachusetts 02138, USA.
Washington University, Department of Physics, St. Louis, Missouri 63130, USA.
Phys Rev Lett. 2025 Mar 7;134(9):096202. doi: 10.1103/PhysRevLett.134.096202.
The negatively charged boron vacancy (V_{B}^{-}) in hexagonal boron nitride (hBN) has garnered significant attention among defects in two-dimensional materials. This owes, in part, to its deterministic generation, well-characterized atomic structure, and optical polarizability at room temperature. We investigate the latter through extensive measurements probing both the ground and excited state polarization dynamics. We develop a semiclassical model based on these measurements that predicts a near-unity degree of spin polarization, surpassing other solid-state spin defects under ambient conditions. Building upon our model, we include the presence of nuclear spin degrees of freedom adjacent to the V_{B}^{-} and perform a comprehensive set of Lindbladian numerics to investigate the hyperfine-induced polarization of the nuclear spins. Our simulations predict a number of important features that emerge as a function of magnetic field which are borne out by experiment.
六方氮化硼（hBN）中带负电荷的硼空位（V${B}^{-}$）在二维材料的缺陷中引起了广泛关注。这在一定程度上归因于其确定性产生、特征明确的原子结构以及室温下的光学极化率。我们通过广泛测量基态和激发态极化动力学来研究后者。基于这些测量，我们开发了一个半经典模型，该模型预测自旋极化度接近1，超过了环境条件下的其他固态自旋缺陷。在我们模型的基础上，我们考虑了与V${B}^{-}$相邻的核自旋自由度的存在，并进行了一组全面的林德布拉德数值计算，以研究超精细诱导的核自旋极化。我们的模拟预测了一些作为磁场函数出现的重要特征，这些特征在实验中得到了证实。
