Readout and control of an endofullerene electronic spin

Abstract

Atomic spins for quantum technologies need to be individually addressed and positioned with nanoscale precision. C-60 fullerene cages offer a robust packaging for atomic spins, while allowing in-situ physical positioning at the nanoscale. However, achieving single-spin level readout and control of endofullerenes has so far remained elusive. In this work, we demonstrate electron paramagnetic resonance on an encapsulated nitrogen spin (N-14@C-60) within a C-60 matrix using a single near-surface nitrogen vacancy (NV) center in diamond at 4.7 K. Exploiting the strong magnetic dipolar interaction between the NV and endofullerene electronic spins, we demonstrate radio-frequency pulse controlled Rabi oscillations and measure spin-echos on an encapsulated spin. Modeling the results using second-order perturbation theory reveals an enhanced hyperfine interaction and zero-field splitting, possibly caused by surface adsorption on diamond. These results demonstrate the first step towards controlling single endofullerenes, and possibly building large-scale endofullerene quantum machines, which can be scaled using standard positioning or self-assembly methods. Encasing a single atom within a fullerene (C-60) cage can create a robustly packaged single atomic spin system. Here, the authors perform electron paramagnetic resonance on a single encased spin using a diamond NV-center, demonstrating the first steps in controlling single spins in fullerene cages.