Abstract
Spin defects in solids offer promising platforms for quantum sensing and memory due to their long coherence times and optical addressability. Here, we integrate a single nitrogen-vacancy (NV) center in diamond with scanning probe microscopy to detect, read out, and spatially map spin-based quantum sensors at the nanoscale. Using the boron vacancy (\({{{{\rm{V}}}}}_{{{{\rm{B}}}}}^{-}\)) center in hexagonal boron nitride—an emerging two-dimensional spin system—as a model, we detect its electron spin resonance indirectly via changes in the spin relaxation time (T1) of a nearby NV center, eliminating the need for optical excitation or fluorescence detection of the \({{{{\rm{V}}}}}_{{{{\rm{B}}}}}^{-}\). Cross-relaxation between NV and \({{{{\rm{V}}}}}_{{{{\rm{B}}}}}^{-}\) ensembles significantly reduces NV T1, enabling quantitative nanoscale mapping of defect densities beyond the optical diffraction limit and clear resolution of hyperfine splitting in isotopically enriched h10B15N. Our method demonstrates interactions between spin sensors in 3D and 2D materials, establishing NV centers as versatile probes for characterizing otherwise inaccessible spin defects.
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The raw data of the main text figures are available in the Zenodo database56. Further data are available from the corresponding author upon request.
References
Chen, X.-D. et al. Quantum enhanced radio detection and ranging with solid spins. Nat. Commun. 14, 1288 (2023).
Alsid, S. T. et al. Solid-state microwave magnetometer with picotesla-level sensitivity. Phys. Rev. Appl. 19, 054095 (2023).
Segawa, T. F. & Igarashi, R. Nanoscale quantum sensing with nitrogen-vacancy centers in nanodiamonds - a magnetic resonance perspective. Prog. Nucl. Magn. Reson. Spectrosc. 134-135, 20–38 (2023).
Qiu, Z., Hamo, A., Vool, U., Zhou, T. X. & Yacoby, A. Nanoscale electric field imaging with an ambient scanning quantum sensor microscope. npj Quantum Inf. 8, 107 (2022).
Bian, K. et al. Nanoscale electric-field imaging based on a quantum sensor and its charge-state control under ambient condition. Nat. Commum. 12, 2457 (2021).
Tzeng, Y.-K. et al. Time-resolved luminescence nanothermometry with nitrogen-vacancy centers in nanodiamonds. Nano Lett. 15, 3945–3952 (2015).
Fujiwara, M. et al. Real-time nanodiamond thermometry probing in vivo thermogenic responses. Sci. Adv. 6, eaba9636 (2020).
Liu, G.-Q., Liu, R.-B. & Li, Q. Nanothermometry with enhanced sensitivity and enlarged working range using diamond sensors. Acc. Chem. Res. 56, 95–105 (2023).
Gottscholl, A. et al. Spin defects in hbn as promising temperature, pressure and magnetic field quantum sensors. Nat. Commun. 12, 4480 (2021).
Lyu, X. et al. Strain quantum sensing with spin defects in hexagonal boron nitride. Nano Lett. 22, 6553–6559 (2022).
Degen, C. L., Reinhard, F. & Cappellaro, P. Quantum sensing. Rev. Mod. Phys. 89, 035002 (2017).
Wu, Y.-C. et al. Nanoscale magnetic ordering dynamics in a high Curie temperature ferromagnet. Nano Letters 25, 1473–1479 (2025).
Jelezko, F. & Wrachtrup, J. Single defect centres in diamond: a review. Phys. Status Solidi A 203, 3207–3225 (2006).
Schirhagl, R., Chang, K., Loretz, M. & Degen, C. L. Nitrogen-vacancy centers in diamond: nanoscale sensors for physics and biology. Annu. Rev. Phys. Chem. 65, 83–105 (2014).
Du, J., Shi, F., Kong, X., Jelezko, F. & Wrachtrup, J. Single-molecule scale magnetic resonance spectroscopy using quantum diamond sensors. Rev. Mod. Phys. 96, 025001 (2024).
Epstein, R. J., Mendoza, F. M., Kato, Y. K. & Awschalom, D. D. Anisotropic interactions of a single spin and dark-spin spectroscopy in diamond. Nat. Phys. 1, 94–98 (2005).
Yao, N. Y. et al. Scalable architecture for a room temperature solid-state quantum information processor. Nat. Commun. 3, 800 (2012).
Doherty, M. W. et al. The nitrogen-vacancy colour centre in diamond. Phys. Rep. 528, 1–45 (2013).
Rondin, L. et al. Magnetometry with nitrogen-vacancy defects in diamond. Rep. Prog. Phys. 77, 056503 (2014).
Casola, F., van der Sar, T. & Yacoby, A. Probing condensed matter physics with magnetometry based on nitrogen-vacancy centres in diamond. Nat. Rev. Mater. 3, 17088 (2018).
Aslam, N. et al. Quantum sensors for biomedical applications. Nat. Rev. Phys. 5, 157–169 (2023).
Liu, Z. et al. Temperature-dependent spin-phonon coupling of boron-vacancy centers in hexagonal boron nitride. Phys. Rev. B 111, 024108 (2025).
Chen, J. et al. Low-dimensional solid-state single-photon emitters. Nanophotonics https://doi.org/10.1515/nanoph-2024-0569 (2025).
Fang, H.-H., Wang, X.-J., Marie, X. & Sun, H.-B. Quantum sensing with optically accessible spin defects in van der Waals layered materials. Light Sci. Appl. 13, 303 (2024).
Guo, Y., Li, J., Dou, R., Ye, H. & Gu, C. Quantum defects in two-dimensional van der Waals materials. Fundam. Res. https://doi.org/10.1016/j.fmre.2024.01.019 (2024).
Clua-Provost, T. et al. Isotopic control of the boron-vacancy spin defect in hexagonal boron nitride. Phys. Rev. Lett. 131, 126901 (2023).
Gong, R. et al. Isotope engineering for spin defects in van der Waals materials. Nat. Commun. 15, 104 (2024).
Gottscholl, A. et al. Initialization and read-out of intrinsic spin defects in a van der Waals crystal at room temperature. Nat. Mat. 19, 540–545 (2020).
Clua-Provost, T. et al. Spin-dependent photodynamics of boron-vacancy centers in hexagonal boron nitride. Phys. Rev. B 110, 014104 (2024).
Vlassiouk, I. V. et al. Defect engineering in large-scale CVD-grown hexagonal boron nitride: Formation, spectroscopy, and spin relaxation dynamics. Small 22, 8 (2026).
Sarkar, S. et al. Identifying luminescent boron vacancies in h-BN generated using controlled He+ ion irradiation. Nano Lett. 24, 43–50 (2024).
Wang, H.-J. et al. Optically detected cross-relaxation spectroscopy of electron spins in diamond. Nat. Commun. 5, 4135 (2014).
Wood, J. D. A. et al. Wide-band nanoscale magnetic resonance spectroscopy using quantum relaxation of a single spin in diamond. Phys. Rev. B 94, 155402 (2016).
Yuan, Z. et al. Charge state dynamics and optically detected electron spin resonance contrast of shallow nitrogen-vacancy centers in diamond. Phys. Rev. Res. 2, 033263 (2020).
Gong, R. et al. Spin relaxometry with solid-state defects: theory, platforms, and applications. Preprint at https://arxiv.org/abs/2602.01521 (2026).
He, G. et al. Quasi-Floquet prethermalization in a disordered dipolar spin ensemble in diamond. Phys. Rev. Lett. 131, 130401 (2023).
Scholten, S. C. et al. Multi-species optically addressable spin defects in a van der Waals material. Nat. Commun. 15, 6727 (2024).
Dresselhaus, M. S., Jorio, A., Souza Filho, A. G. & Saito, R. Defect characterization in graphene and carbon nanotubes using Raman spectroscopy. Philos. Trans. R. Soc. A 368, 5355–5377 (2010).
Eckmann, A. et al. Probing the nature of defects in graphene by Raman spectroscopy. Nano Lett. 12, 3925–3930 (2012).
Lee, C. et al. Investigating heterogeneous defects in single-crystalline WS2 via tip-enhanced Raman spectroscopy. npj 2D Mater. Appl. 6, 67 (2022).
Zhang, P. et al. Insights into the role of defects on the Raman spectroscopy of carbon nanotube and biomass-derived carbon. Carbon 222, 118998 (2024).
Rugar, D. et al. Proton magnetic resonance imaging using a nitrogen-vacancy spin sensor. Nat. Nanotech. 10, 120–124 (2015).
Wang, P. et al. Nanoscale magnetic imaging of ferritins in a single cell. Sci. Adv. 5, eaau8038 (2019).
Krečmarová, M. et al. Optical contrast and Raman spectroscopy techniques applied to few-layer 2D hexagonal boron nitride. Nanomaterials 9, 1047 (2019).
Linderälv, C., Wieczorek, W. & Erhart, P. Vibrational signatures for the identification of single-photon emitters in hexagonal boron nitride. Phys. Rev. B 103, 115421 (2021).
Barry, J. F. et al. Sensitivity optimization for NV-diamond magnetometry. Rev. Mod. Phys. 92, 015004 (2020).
Gong, R. et al. Coherent dynamics of strongly interacting electronic spin defects in hexagonal boron nitride. Nat. Commun. 14, 3299 (2023).
Fraunié, J. et al. Charge state tuning of spin defects in hexagonal boron nitride. Nano Lett. 25, 5836–5842 (2025).
Wood, J. D. A. et al. Microwave-free nuclear magnetic resonance at molecular scales. Nat. Commun. 8, 15950 (2017).
Grinolds, M. S. et al. Nanoscale magnetic imaging of a single electron spin under ambient conditions. Nat. Phys. 9, 215–219 (2013).
Sushkov, A. O. et al. Magnetic resonance detection of individual proton spins using quantum reporters. Phys. Rev. Lett. 113, 197601 (2014).
Shi, F. et al. Single-protein spin resonance spectroscopy under ambient conditions. Science 347, 1135–1138 (2015).
Sun, H. et al. Room-temperature hybrid 2D-3D quantum spin system for enhanced magnetic sensing and many-body dynamics. npj Quantum Inf. 12, 10 (2025).
Liu, S. et al. Single crystal growth of millimeter-sized monoisotopic hexagonal boron nitride. Chem. Mater. 30, 6222–6225 (2018).
Janzen, E. et al. Boron and nitrogen isotope effects on hexagonal boron nitride properties. Adv. Mater. 36, 2306033 (2024).
Melendez, A. L. et al. Data for probing boron vacancy defects in hbn via single spin relaxometry. Zenodo https://doi.org/10.5281/zenodo.18520527 (2026).
Acknowledgements
The scanning NV microscopy, hBNnat synthesis, and nanofabrication were supported by the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. Spin relaxation measurements were supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy. The RF controls were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. Support for h10B15N crystal growth was provided by the Office of Naval Research, award number N00014-22-1-2582. Neutron irradiation of the h10B15N crystals was supported by the U.S. Department of Energy, Office of Nuclear Energy, under DOE Idaho Operations Office Contract DE-AC07-051D13417 as part of a Nuclear Science User Facilities experiment. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains, and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). R.G., G.H. and C.Z. acknowledge support from the National Science Foundation under grant No. 2514391.
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H.Z. conceived the project and performed the NV relaxometry experiments. A.L.M. and H.Z. analyzed the data and co-wrote the manuscript with input from all other authors. A.L.M., Y.W., R.G., and G.H. developed the theoretical model, with additional input from L.L., C.Z., and J.T.D. R.G., G.H., and C.Z. performed the Monte Carlo simulation and quantified the defect density. I.V.V. synthesized the hBNnat samples and performed optical spectroscopy. T.P. and J.H.E. synthesized the h10B15N samples and organized the neutron irradiation. S.R. conducted the helium ion implantation. S.G. fabricated the coplanar waveguide. Y.C.W. and B.J.L. assisted with the microwave delivery setup. A.-P.L., S.J., and B.J.L. provided technical support for the scanning NV microscope measurements.
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Melendez, A.L., Gong, R., He, G. et al. Probing boron vacancy defects in hBN via single spin relaxometry. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70545-6
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DOI: https://doi.org/10.1038/s41467-026-70545-6
