Quantum Center Engineering of Silicon Carbide for ODMR based Space Magnetometry Applications

In this study, we investigate the parameter space of irradiation treatment and operation parameters of negatively charged silicon vacancies (V − Si ) in 4H and 6H silicon carbide (SiC), to optimize performance metrics for quantum magnetometry applications: Exploring a 2MeV electron irradiation fluence range from 1014 to 1019 electrons/cm2, we extract a linear power-law for the creation of V − Si independent of their symmetry (C3v or Td ) and, more importantly, a superlinear behavior ρV − Si ∝ φ 1.1 e− for optically detected magnetic resonance (ODMR)-active centers. This behavior is favorable for all ODMR-based quantum applications that require ensembles of V2/V3 centers. In terms of ODMR-based magnetometry, we analyze the interplay of V − Si density, laser power, and RF driving field across multiple orders of magnitude, achieving single-digit nT/√Hz magnetic field sensitivities. By examining the interaction between natural linewidth and spin density, we estimate a spin-projection noise limit in the pT/√Hz range. This figure of merit, along with the absence of any magnetic bias field requirements common to other material systems, highlights the potential of SiC-based compact near-zero field magnetometers, which are particularly attractive for airborne and space applications.

本研究针对4H型与6H型碳化硅（silicon carbide, SiC）中的负电荷硅空位（negatively charged silicon vacancies, V⁻_Si）的辐照处理参数与运行参数空间展开系统探究，旨在优化量子磁测应用的性能指标：我们在2MeV电子辐照注量介于10¹⁴至10¹⁹ 电子/平方厘米的范围内开展实验，发现负电荷硅空位的生成遵循与其对称性（C3v或Td对称）无关的线性幂律；更关键的是，光探测磁共振（optically detected magnetic resonance, ODMR）活性中心的V⁻_Si密度满足超线性关系ρ_V⁻_Si ∝ φ_e^1.1。该特性对于所有需要V2/V3缺陷集合体的光探测磁共振类量子应用均具备优势。针对光探测磁共振磁测场景，我们在多个数量级范围内分析了V⁻_Si密度、激光功率与射频驱动场之间的相互作用，实现了个位数纳特斯拉/根号赫兹（nT/√Hz）的磁场灵敏度。通过探究自然线宽与自旋密度之间的相互作用，我们估算出了皮特斯拉/根号赫兹（pT/√Hz）量级的自旋投影噪声极限。该品质因数，结合无需施加其他材料体系普遍所需的磁偏置场这一优势，凸显了基于碳化硅的紧凑型近零场磁强计的应用潜力，这类磁强计在机载与航天领域尤为具备吸引力。