Department of Physics, University of California, Santa Barbara, California 93106, USA.
Phys Rev Lett. 2019 Feb 22;122(7):076101. doi: 10.1103/PhysRevLett.122.076101.
The charge degree of freedom in solid-state defects fundamentally underpins the electronic spin degree of freedom, a workhorse of quantum technologies. Here we measure, analyze, and control charge-state behavior in individual near-surface nitrogen-vacancy (NV) centers in diamond, where NV^{-} hosts the metrologically relevant electron spin. We find that NV^{-} initialization fidelity varies between individual centers and over time; we alleviate the deleterious effects of reduced NV^{-} initialization fidelity via logic-based initialization. Importantly, we also show that NV^{-} can ionize in the dark on experimentally relevant timescales, and we introduce measurement protocols that mitigate the compromising effects of charge conversion on spin measurements. We identify tunneling to a single local electron trap as the mechanism for ionization in the dark, and we develop novel NV-assisted techniques to control and read out the trap charge state. Our understanding and command of the NV's local electrostatic environment will simultaneously guide materials design and provide unique functionalities with NV centers.
在固态缺陷中，电荷自由度从根本上支撑着电子自旋自由度，这是量子技术的主要工具。在这里，我们测量、分析和控制金刚石中单个近表面氮空位（NV）中心的电荷态行为，其中 NV^{-} 承载着与计量学相关的电子自旋。我们发现，NV^{-}的初始化保真度在各个中心之间以及随时间变化而变化；我们通过基于逻辑的初始化来减轻 NV^{-}初始化保真度降低的有害影响。重要的是，我们还表明，NV^{-}可以在实验相关的时间尺度上在黑暗中离子化，并且我们引入了测量协议，以减轻电荷转换对自旋测量的不利影响。我们确定隧道到单个局部电子陷阱是黑暗中离子化的机制，并开发了新的 NV 辅助技术来控制和读出陷阱电荷状态。我们对 NV 局部静电环境的理解和控制将同时指导材料设计，并为 NV 中心提供独特的功能。
