金刚石中全同NV色心系统的制备及旋转几何相位研究

The research about the geometric phase is very important. It has been theoretically illustrated that NV center in diamond could be used to measure the geometric phase as an ideal solid state object of spin manipulation. However, it have not been observed experimentally due to the poor sensitivity. The key for improving the sensitivity is to obtain the identical NV center with high density. Aiming at this problem, this project will implement the carrier doping and controlling of valance state by using ion implantation, electron irradiation, annealing etc. At the same time, positron annihilation and optical spectroscopy will be combined to precisely detect the defects. Furthermore, through the detection and analysis of defect properties produced under different fabrication condition, we will study the dynamical mechanism of producing, mobility, and recombination of defects, and optimize the fabrication condition of identical NV center with high density. Based on these studies we will develop a method of measuring geometric phase by rotating magnetic field.

量子几何相位的研究是一个重要的科学问题。金刚石中的NV色心作为理想的固态自旋调控对象，理论上已经证明了其可以用于几何相位的测量。但是受制于灵敏度的难以提高，目前在实验上还未能成功观察到该效应。而提高测量灵敏度的关键是必须获得高密度的全同NV色心体系。本项目将围绕该问题，拟通过离子注入、电子辐照和退火等方法来实现载流子掺杂和精密的价态控制；同时将发展一种正电子湮没和光谱学相结合的方法来对缺陷进行准确的检测；通过对不同制备条件下的缺陷性质进行检测和分析，来研究金刚石中缺陷的产生、运动和复合等动力学行为，寻找实现高密度、全同NV色心的方法和条件。在此基础上我们还将发展通过旋转磁场的方法来实现几何相位的测量。

金刚石中的NV色心作为室温和零磁场下的量子比特，在量子计算、磁场测量和惯性导航等方面具有很大应用前景。制备高浓度的NV色心是其走向实际应用的第一步。本项目通过电子注入和退火技术在金刚石中产生NV色心，通过荧光特性来表征NV色性的浓度。通过大量系统的实验，研究分析了NV色心形成的动力学，得到了NV色心浓度与退火温度的玻尔兹曼模型，最终实现了NV色心浓度的可控制备。结果表明在800度下进行2小时退火可以制备出最大浓度的NV色心。对于制备好的样品，在我们搭建的光探测磁共振（ODMR）系统上进行了ODMR光谱的测量。我们还将ODMR探测装置和转动系统相结合，并在该平台上测量了NV色心样品在旋转状态下的ODMR光谱。结果发现ODMR信号随着转速的提高而展宽劈裂。通过Barnett效应分析了ODMR信号宽度和转速的关系，在原理上验证了NV色心实现惯性测量的可能性。