error correction methods [22 ,23]. The NV-NV separation within a single NV site is determined by the NV density. With an 15N+ implantation dosage of 1013 cm-2 and conversion efficiency of 6 %, the diamond sample used in the present work has d = 15 nm. By increasing the implantation dosage and irradiating with neutrons or electrons, a minimum separation of dmin 4 nm (corresponding to an NV-NV dipolar ≈ interaction strength 0.6 MHz) may be achievable, although the sample at this density ≈ might suffer from low fluorescence contrast due to NV-/NV0 charge state conversion and a shorter T2* due to remaining paramagnetic impurities. The spacing between NV sites, on the other hand, is limited by the NV site area, and thus cannot be smaller than Dmin nm. If two NV centres are randomly picked from each of two NV sites with area A ≈10 and spacing D, the mean and standard deviation of separation between them are given by ~D and ~A1/2, respectively. Supplementary References [1] Rugar, D., Budakian, R., Mamin, H. J. & Chui, B. W. Single spin detection by magnetic resonance force microscopy. 430, 329–332 (2004). Nature [2] Degen, C. L., Poggio, M., Mamin, H. J., Rettner, C. T. & Rugar, D. Nanoscale magnetic resonance imaging. 106, 1313-1317 Proc. Natl. Acad. Sci. U.S.A. (2009). [3] Mamin, H. J., Rettner, C. T., Sherwood, M. H., Gao, L. & Rugar, D. High dysprosium tips for magnetic resonance force microscopy. Applied 100, 013102 (2012). Physics Letters [4] Glover P. & Mansfield P. Limits to magnetic resonance microscopy. Rep. Prog. 65, 1489-1511 (2002). Phys. [5] Lee, S. C., One micrometer resolution NRM microscopy. et al. J. Magn. Reson. 150, 207-213 (2001).
error correction methods [22 ,23]. The NV-NV separation within a single NV site is determined by the NV density. With an 15N+ implantation dosage of 1013 cm-2 and conversion efficiency of 6 %, the diamond sample used in the present work has d = 15 nm. By increasing the implantation dosage and irradiating with neutrons or electrons, a minimum separation of dmin ≈ 4 nm (corresponding to an NV-NV dipolar interaction strength ≈ 0.6 MHz) may be achievable, although the sample at this density might suffer from low fluorescence contrast due to NV-/NV0 charge state conversion and a shorter T2* due to remaining paramagnetic impurities. The spacing between NV sites, on the other hand, is limited by the NV site area, and thus cannot be smaller than Dmin ≈10 nm. If two NV centres are randomly picked from each of two NV sites with area A and spacing D, the mean and standard deviation of separation between them are given by ~D and ~A1/2, respectively. Supplementary References [1] Rugar, D., Budakian, R., Mamin, H. J. & Chui, B. W. Single spin detection by magnetic resonance force microscopy. Nature 430, 329–332 (2004). [2] Degen, C. L., Poggio, M., Mamin, H. J., Rettner, C. T. & Rugar, D. Nanoscale magnetic resonance imaging. Proc. Natl. Acad. Sci. U.S.A. 106, 1313-1317 (2009). [3] Mamin, H. J., Rettner, C. T., Sherwood, M. H., Gao, L. & Rugar, D. High dysprosium tips for magnetic resonance force microscopy. Applied Physics Letters 100, 013102 (2012). [4] Glover P. & Mansfield P. Limits to magnetic resonance microscopy. Rep. Prog. Phys. 65, 1489-1511 (2002). [5] Lee, S. C., et al. One micrometer resolution NRM microscopy. J. Magn. Reson. 150, 207-213 (2001).
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