标题： 基于钻石中超浅单氮空位中心的量子传感器相干保护方案 显示英文标题

标题： A Coherence-Protection Scheme for Quantum Sensors Based on Ultra-Shallow Single Nitrogen-Vacancy Centers in Diamond

摘要： 近期在钻石表面工程方面的进展使得有可能稳定金刚石中深度为7到30纳米的氮空位（NV）量子传感器的电荷状态，并且原则上可以消除表面的电荷噪声。 然而，在将NV中心放置在0.5到2纳米深处的同时增加量子传感器的作用体积仍然是一个挑战，因为这会受到来自金刚石表面终止层中波动的核自旋产生的磁噪声的限制。 在这里，我们通过第一性原理模拟表明，利用表面诱导的应变和小的恒定磁场之间的相互作用，在富$^{12}$C金刚石中，超浅1纳米深的NV中心的自旋相干时间可以在室温下的自旋-声子极限附近显著提高。 我们还证明了我们的协议对天然金刚石中的$\sim$10纳米深的NV中心也有益处，在那里中心对小恒定磁场方向的可变相干特性建立了纳米尺度的矢量磁强计。 显示英文摘要

摘要： Recent advances in the engineering of diamond surfaces make it possible to stabilize the charge state of 7-30 nanometers deep nitrogen-vacancy (NV) quantum sensors in diamond and to remove the charge noise at the surface principally. However, it is still a challenge to simultaneously increase the action volume of the quantum sensor by placing NV centers 0.5-2 nanometers deep and to maintain their favorable spin coherence properties which are limited by the magnetic noise from the fluctuating nuclear spins of the surface termination of diamond. Here we show by means of first principles simulations that leveraging the interplay of the surface-induced strain and small constant magnetic fields, the spin coherence times of the ultra-shallow 1-nanometer deep NV center can be significantly enhanced near the spin-phonon limited regime at room temperature in $^{12}$C enriched diamonds. We demonstrate that our protocol is beneficial to $\sim$10-nanometers deep NV centers in natural diamond too where the variable coherence properties of the center to the direction of the small constant magnetic fields establish vector magnetometry at the nanoscale.