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 13C 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–13C 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. Interactions between the nitrogen-vacancy (NV) centre in diamond and proximal spins offer a fertile ground for studying the coherent dynamics of multi-spin systems [1]–[4] and suggest potential implementations for quantum information processing schemes [4]–[7]. Moreover, the discrete lattice sites available to substitutional spin impurities such as 13C can be exploited to obtain information about the electronic spin density of the NV centre [8, 9]. While conventional ensemble electron paramagnetic resonance (EPR), electron–nuclear double resonance (ENDOR) and nuclear magnetic resonance (NMR) techniques can measure electron–nuclear spin interactions for the native 14N or 15N and a few strongly coupled 13C 4 Author to whom any correspondence should be addressed. New Journal of Physics 13 (2011) 025021 1367-2630/11/025021+09$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft