Hyperfine Structure and Exchange Coupling of Vacancy-Induced Ce$^{3+}$ Spin Centers in Nuclear-Spin-Dilute CeO$_2$

Summary

arXiv:2607.12080v1 Announce Type: new Abstract: Oxygen vacancies in ceria CeO$_2$ donate electrons that localize as Ce$^{3+}$ ($4f^1$, $S=1/2$) small polarons, creating rare-earth spin centers through native defect chemistry rather than implantation or extrinsic doping. We investigate the magnetic environment of these centers using first-principles PBE$+U$ calculations with a linear-response Hubbard parameter ($U=5.8382$ eV), hyperfine tensors from the all-electron reconstruction of the projector-augmented-wave method, and Korringa-Kohn-Rostoker exchange calculations within the coherent-potential approximation. Four vacancy configurations spanning concentrations from $3.125\%$ to $12.5\%$ are considered.