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We report extensive lattice dynamical calculations of the newly discovered infinite-layer iron oxides SrFeO2 and CaFeO2. For SrFeO2, the parameters of the interatomic potential have been determined to reproduce the zone-centre phonon frequencies reported using ab-initio calculations. Further we have extended the potential model for calculations of CaFeO2. The potential parameters are found to be transferable between the two compounds, and are used to calculate the phonon spectra in the whole Brillouin zone and several thermodynamic properties for these compounds. The calculations show fair agreement with the available experimental data of structure, thermal expansion, and mean-squared amplitudes of the atoms.
The electronic structure is found to be understandable in terms of free-atom term values and universal interorbital coupling parameters, since self-consistent tight-binding calculations indicate that Coulomb shifts of the d-state energies are small.
Superconducting nickelates appear to be difficult to synthesize. Since the chemical reduction of ABO3 (A: rare earth; B transition metal) with CaH2 may result in both, ABO2 and ABO2H, we calculate the topotactic H binding energy by density functional
We have used density-functional-theory methods and the ab initio random structure searching (AIRSS) approach to predict stable structures and stoichiometries of mixtures of iron and oxygen at high pressures. Searching was performed for 12 different s
The effect of silica-promotion on the reduction of iron oxides in hydrogen was investigated using in situ X-ray diffraction and aberration-corrected transmission electron microscopy to understand the mechanism of reduction and the identity of the iro
Manipulation of octahedral distortion at atomic length scale is an effective means to tune the physical ground states of functional oxides. Previous work demonstrates that epitaxial strain and film thickness are variable parameters to modify the octa