Highly Coherent Nitrogen-Vacancy Centers in Diamond via Rational High-Pressure and High-Temperature Synthesis and Treatment

Abstract

The high-pressure and high-temperature (HPHT) diamonds with well-controlled defects and low stress offer an ideal host substrate for the fields of quantum information science; however, fabrication of quantum-grade HPHT diamonds remains a pressing challenge. Here, a major advance in generating highly coherent nitrogen-vacancy (NV) centers, a promising spin defect in diamonds, via tailored HPHT synthesis and postgrown annealing treatment is reported. The resulting well-dispersed single NV− centers in type-IIa diamonds exhibit long spin coherence times comparable to that of the reported chemical vapor deposition diamonds. Moreover, high-density NV− ensembles in 〈100〉-grown type-Ib diamonds with superb zero-phonon lines considerably sharper than those of native NV− centers in as-grown diamonds, together with low splitting of resonances are produced. These findings demonstrate a superior synthesis and optimization protocol for creating high-quality NV− centers avoiding lattice damage in diamond to meet the stringent requirements for a wide range of emerging quantum technologies.