Influence of Irradiation on Defect Spin Coherence in Silicon Carbide

Irradiation-induced lattice defects in silicon carbide (SiC) have already exceeded their previous reputationas purely performance inhibiting. With their remarkable quantum properties, such as longroom-temperature spin coherence and the possibility of downscaling to single-photon-source level, theyhave proven to be promising candidates for a multitude of quantum-information applications. One of themost crucial parameters of any quantum system is how long its quantum coherence can be preserved. Byusing the pulsed optically detected magnetic resonance (ODMR) technique, we investigate the spin-latticerelaxation time (T1) and spin-coherence time (T2) of silicon vacancies in 4H-SiC created by neutron, electron,and proton irradiation in a broad range of fluences. We also examine the effect of irradiation energyand sample annealing.We establish a robustness of the T1 time against all types of irradiation and reveal auniversal scaling of the T2 time with the emitter density. Our results can be used to optimize the coherenceproperties of silicon-vacancy qubits in SiC for specific tasks.

碳化硅（SiC）中辐照诱导的晶格缺陷已突破以往仅被视为性能抑制剂的认知局限。凭借其卓越的量子特性——如室温下长自旋相干性以及可缩小至单光子源级别的潜力——这些缺陷已被证明是众多量子信息应用领域极具前景的候选者。任何量子系统最核心的参数之一，是其量子相干性能够维持的时长。通过脉冲光探测磁共振（pulsed optically detected magnetic resonance, ODMR）技术，我们研究了经中子、电子和质子在宽注量范围内辐照4H-SiC所产生的硅空位的自旋晶格弛豫时间（spin-lattice relaxation time, T1）与自旋相干时间（spin-coherence time, T2），同时考察了辐照能量与样品退火的影响。我们证实了T1对所有辐照类型的鲁棒性，并揭示了T2随发射器密度变化的普适标度规律。本研究结果可用于优化SiC中硅空位量子比特的相干特性，以适配特定任务需求。