Berlin 2024 – scientific programme

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MA: Fachverband Magnetismus

MA 29: Spin-Dependent Phenomena in 2 D

MA 29.13: Talk

Wednesday, March 20, 2024, 18:15–18:30, EB 202

Hyperfine interactions in open-shell planar sp²-carbon nanostructures — Sanghita Sengupta¹, Thomas Frederiksen^1,2, and •Géza Giedke^1,2 — ¹Donostia International Physics Center (DIPC), E-20018, Donostia-San Sebastián, Spai — ²IKERBASQUE, Basque Foundation for Science, E-48013, Bilbao, Spain

We investigate hyperfine interaction (HFI) using density-functional theory for several open-shell planar sp²-carbon nanostructures displaying π magnetism such as [n]triangulenes and graphene nanoribbons. Our results indicate that HFI can reach 100 MHz and that isotropic Fermi contact and anisotropic dipolar terms contribute in comparable strength, rendering the HFI markedly anisotropic. Using these results we obtain empirical models using generic sp²-HFI fit parameters that connect the HFI to the π-spin polarizations at carbon sites only. These models successfully describe the Fermi contact and dipolar contributions for 13 C and 1 H nuclei and allow to obtain hyperfine tensors for large systems where existing methodology is not suitable or computationally too expensive. Implications of the obtained HFI for electron-spin decoherence, dynamical nuclear polarization, and for coherent nuclear dynamics are discussed.

Keywords: hyperfine interaction, graphene nanostructures