Abstract
A detailed investigation of the electronic structure in the neighborhood of Cd impurities in ${\mathrm{CeO}}_{2}$ has been performed by ab initio calculations to elucidate the interplay between the oxygen vacancies and electric quadrupole interactions. The quadrupole frequency related to the major component of the electric-field gradient (EFG) at impurities sites from its neighboring charge density as well as its symmetry were calculated by simulating oxygen vacancies at oxygen nearest neighbor of Cd. Results show a very good agreement with experimental hyperfine interactions measurements at the $^{111}\mathrm{Cd}$ nucleus replacing Ce at ${\mathrm{CeO}}_{2}$. A systematic mapping of oxygen vacancies in ${\mathrm{CeO}}_{2}$ supercells was proposed within the framework of density-functional theory using the wien2k code focusing on the electronic distribution in the vicinity of Cd impurities. Results show that the calculated values of EFG crucially depend on impurity-vacancy complex position and the striking axial symmetry observed when an oxygen monovancy is at the nearest neighborhood of Cd is explained by a rearrangement of its $p$ orbitals.
Published Version
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