Electron Spin Decoherence of Nitrogen-Vacancy Center Coupled to Multiple Spin Baths**Supported by the National Basic Research Program of China under Grant Nos 2014CB921402 and 2015CB921103, the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB07010300, and the National Natural Science Foundation of China under Grant No 11574386.

Abstract

We present the experimental results of nitrogen-vacancy (NV) electron spin decoherence, which are linked to the coexistence of electron spin bath of nitrogen impurity (P1 center) and 13C nuclear spin bath. In previous works, only one dominant decoherence source is studied: P1 electron spin bath for type-Ib diamond; or 13C nuclear spin bath for type-IIa diamond. In general, the thermal fluctuation from both spin baths can be eliminated by the Hahn echo sequence, resulting in a long coherence time (T2) of about 400 μs. However, in a high-purity type-IIa diamond where 13C nuclear spin bath is the dominant decoherence source, dramatic decreases of NV electron spin T2 time caused by P1 electron spin bath are observed under certain magnetic field. We further apply the engineered Hahn echo sequence to confirm the decoherence mechanism of multiple spin baths and quantitatively estimate the contribution of P1 electron spin bath. Our results are helpful to understand the NV decoherence mechanisms, which will benefit quantum computing and quantum metrology.