Defect Trapping and Phase Separation in Chemically Doped Bulk AgF₂.

ABSTRACT: We report a computational survey of chemical doping of silver(II) fluoride, which has recently attracted attention as an analogue of La₂CuO₄-a known precursor of high-temperature superconductors. By introducing fluorine defects (vacancies or interstitial adatoms) into the crystal structure, we obtain nonstoichiometric, electron- and hole-doped polymorphs of AgF_2±x. We find that the ground-state solutions show a strong tendency for localization of defects and of the associated electronic states, and the resulting doped phases exhibit insulating or semiconducting properties. Furthermore, the distribution of Ag(I)/Ag(III) sites which appear in the crystal structure points to the propensity of the AgF₂ system for phase separation upon chemical doping, which is in line with observations from previous experimental attempts. Overall, our results indicate that chemical modification may not be a feasible way to achieve doping in bulk silver(II) fluoride, which is considered essential for the emergence of high-T_c superconductivity.

SUBMITTER: Grzelak A 

PROVIDER: S-EPMC7877723 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature