Revealing the complex nature of bonding in binary high-pressure compound FeO${}_2$

Abstract

Extreme pressures and temperatures are known to drastically affect the chemistry of iron oxides resulting in numerous compounds forming homologous series $n$FeO$\cdot m$Fe${}_2$O${}_3$ and the appearance of FeO${}_2$. Here, based on the results of \emph{in situ} single-crystal X-ray diffraction, Mössbauer spectroscopy, X-ray absorption spectroscopy, and DFT+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 two. 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.

References in corpus (17)

• Continuous-time Monte Carlo methods for quantum impurity models
• CrO2: a self-doped double exchange ferromagnet
• Self-consistency over the charge-density in dynamical mean-field theory: a linear muffin-tin implementation and some physical implications
• LDA+DMFT implemented with the pseudopotential plane-wave approach
• Metal-Insulator Transition and Lattice Instability of Paramagnetic V2O3
• Magnetic Collapse and the Behavior of Transition Metal Oxides at High Pressure
• Metal-insulator transition and local-moment collapse in FeO under pressure
• Theoretical and experimental evidence of a site-selective Mott transition in Fe2O3 under pressure
• Unexpected 3+ valence of iron in FeO${}_2$, a geologically important material lying "in between" oxides and peroxides
• Metal-Insulator Transition and the Role of Electron Correlation in FeO2
• Stable magnesium peroxide at high pressure
• Emergence of quantum critical charge and spin-state fluctuations near the pressure-induced Mott transition in MnO, FeO, CoO, and NiO
• Effect of electron correlations on the electronic structure and phase stability of FeSe upon lattice expansion
• Correlation strength, Lifshitz transition and the emergence of a two- to three-dimensional crossover in FeSe under pressure
• Electronic Spin transition in FeO${}_2$: evidence for Fe(II) with peroxide O${}_2^{2-}$
• Charge disproportionation and site-selective local magnetic moments in the post-perovskite-type Fe${}_2$O${}_3$ under ultra-high pressures
• Pressure-induced spin pairing transition of Fe${}^{3+}$ in oxygen octahedra

Cited by in corpus (9)

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• Correlation strength, orbital-selective incoherence, and local moments formation in the magnetic MAX-phase Mn${}_2$GaC
• Metal-insulator transition and local-moment collapse in negative charge-transfer CaFeO${}_3$ under pressure
• Phase transitions and spin-state of iron in FeO at the conditions of Earth's deep interior
• Electronic correlations and long-range magnetic ordering in NiO tuned by pressure
• Metallic nature and site-selective magnetic collapse in iron oxide Fe4O5 at the extreme conditions of Earth's deep interior
• Site-selective magnetic moment collapse in compressed Fe5O6
• Valence Transition Theory of the Pressure-Induced Dimensionality Crossover in Superconducting Sr${}_{14-x}$Ca${}_x$Cu${}_{24}$O${}_{41}$
• Interplay of electronic correlations and chemical bonding in FeN${}_2$ under pressure