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arXiv · 2101.02650

Nanoscale spin detection of copper ions using double electron-electron resonance at room temperature

Kai Zhang·Shreya Ghosh·Sunil Saxena·M. V. Gurudev Dutt
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Abstract

We report the nanoscale spin detection and electron paramagnetic resonance (EPR) spectrum of copper (Cu$^{2+}$) ions via double electron-electron resonance with single spins in diamond at room temperature and low magnetic fields. We measure unexpectedly narrow EPR resonances with linewidths $\sim 2-3$ MHz from copper-chloride molecules dissolved in poly-lysine. We also observe coherent Rabi oscillations and hyperfine splitting from single Cu$^{2+}$ ions, which could be used for dynamic nuclear spin polarization and higher sensitivity of spin detection. We interpret and analyze these observations using both spin hamiltonian modeling of the copper-chloride molecules and numerical simulations of the predicted DEER response, and obtain a sensing volume $\sim (250 \text{nm})^3$. This work will open the door for copper-labeled EPR measurements under ambient conditions in bio-molecules and nano-materials.

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Kai Zhang, Shreya Ghosh, Sunil Saxena, M. V. Gurudev Dutt. 2021-08-31. Nanoscale spin detection of copper ions using double electron-electron resonance at room temperature. https://doi.org/10.1103/physrevb.104.224412

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