Auteur(s): Koemets E., Leonov I., Bykov M., Bykova E., Chariton S., Aprilis G., Fedotenko T., Clement S., Rouquette J., Haines Julien, Cerantola V., Glazyrin K., Mccammon C., Prakapenka V. b., Hanfland M., Liermann H.-P., Svitlyk V., Torchio R., Rosa A. d., Irifune T., Ponomareva A. v., Abrikosov I. a., Dubrovinskaia N., Dubrovinsky L.
(Article) Publié:
Physical Review Letters, vol. 126 p.106001 (2021)
Texte intégral en Openaccess : 
Ref HAL: hal-03268215_v1
DOI: 10.1103/PhysRevLett.126.106001
Exporter : BibTex | endNote
Résumé:
Extreme pressures and temperatures are known to drastically affect the chemistry of iron oxides, resulting in numerous compounds forming homologous series nFeOmFe_{2}O_{3} and the appearance of FeO_{2}. Here, based on the results of in situ single-crystal x-ray diffraction, Mössbauer spectroscopy, x-ray absorption spectroscopy, and density-functional theory+dynamical mean-field theory calculations, we demonstrate that iron in high-pressure cubic FeO_{2} and isostructural FeO_{2}H_{0.5} is ferric (Fe^{3+}), and oxygen has a formal valence less than 2. Reduction of oxygen valence from 2, common for oxides, down to 1.5 can be explained by a formation of a localized hole at oxygen sites.