Decoherence of ensembles of nitrogen-vacancy centers in diamond
Erik Bauch, Swati Singh, Junghyun Lee, Connor Hart, Jennifer M. Schloss, Matthew Turner, John F. Barry, Linh Pham, Nir Bar‐Gill, Susanne F. Yelin, Ronald L. Walsworth
Abstract
We present a combined theoretical and experimental study of solid-state spin decoherence in an electronic spin bath, focusing specifically on ensembles of nitrogen-vacancy (NV) centers in diamond and the associated substitutional nitrogen spin bath. We perform measurements of NV spin free-induction decay (FID) times ${T}_{2}^{*}$ and spin-echo coherence times ${T}_{2}$ in 25 diamond samples with nitrogen concentrations [N] ranging from 0.01 to 300 ppm. We introduce a microscopic model and perform numerical simulations to quantitatively explain the degradation of both ${T}_{2}^{*}$ and ${T}_{2}$ over four orders of magnitude in [N]. Our analysis enables us to describe the NV ensemble spin coherence decay shapes as emerging consistently from the contribution of many individual NV centers.