Dynamic-nuclear-polarization-weighted spectroscopy of multi-spin electronic-nuclear clusters

• Main Authors: Pigliapochi, Roberta, Pagliero, Daniela, Buljubasich, Lisandro, Lozovoi, Artur, Acosta, Rodolfo H, Zangara, Pablo R, Meriles, Carlos A
• Format: Journal Article
• Language: English
• Published: 22-06-2023
• Subjects: Physics - Mesoscale and Nanoscale Physics
• DOI: 10.48550/arxiv.2306.13193

Phys. Rev. B 107, 214202 (2023) Nuclear spins and paramagnetic centers in a solid randomly group to form
clusters featuring nearly-degenerate, hybrid states whose dynamics are central
to processes involving nuclear spin-lattice relaxation and diffusion. Their
characterization, however, has proven notoriously difficult mostly due to their
relative isolation and comparatively low concentration. Here, we combine
field-cycling experiments, optical spin pumping, and variable radio-frequency
(RF) excitation to probe transitions between hybrid multi-spin states formed by
strongly coupled electronic and nuclear spins in diamond. Leveraging bulk
nuclei as a collective time-integrating sensor, we probe the response of these
spin clusters as we simultaneously vary the applied magnetic field and RF
excitation to reconstruct multi-dimensional spectra. We uncover complex nuclear
polarization patterns of alternating sign that we qualitatively capture through
analytical and numerical modeling. Our results unambiguously expose the impact
that strongly-hyperfine-coupled nuclei can have on the spin dynamics of the
crystal, and inform future routes to spin cluster control and detection.