13C hyperfine interactions in the nitrogen-vacancy centre in diamond

The electronic spin associated with the nitrogen-vacancy (NV) centre in diamond interacts with an environment formed by isotopic impurities and paramagnetic defects; the strength of these interactions depends on the location of each impurity relative to the NV centre. From the electron spin resonance spectra of individual NV centres we infer the possible values and signs of hyperfine splittings from nearby C-13 nuclear spins at different lattice sites. Moreover, single-defect-centre nuclear magnetic resonance allows the examination of some of the inhomogeneities associated with the mesoscopic environment of NV-C-13 systems. These measurements provide a check on ab initio calculations of electron spin density and have relevance for potential applications in nuclear spin quantum registers.