Decoherence of Near-Surface Nitrogen-Vacancy Centers Due to Electric Field Noise

We show that electric field noise from surface charge fluctuations can be a significant source of spin decoherence for near-surface nitrogen-vacancy (NV) centers in diamond. This conclusion is based on the increase in spin coherence observed when the diamond surface is covered with high-dielectric-constant liquids, such as glycerol. Double-resonance experiments show that improved coherence occurs even though the coupling to nearby electron spins is unchanged when the liquid is applied. Multipulse spin-echo experiments reveal the effect of glycerol on the spectrum of NV frequency noise.