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- Kollar, J., et al.
(author)
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Metal surfaces : Surface, step and kink formation energies
- 2000
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In: Physica status solidi. B, Basic research. - : WILEY-V C H VERLAG GMBH. - 0370-1972 .- 1521-3951. ; 217:1, s. 405-418
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Journal article (peer-reviewed)abstract
- We review the surface, step, and kink energies in monoatomic metallic systems. A systematic comparison is given between the theoretical results based on density functional theory and available experimental data. Our calculated values are used to predict the equilibrium shapes of small metal particles, monoatomic surface islands, and the instability of different surface geometries.
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3. |
- Magyari-Kope, B., et al.
(author)
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High-pressure structure of ScAlO3 perovskite
- 2002
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In: Journal of Geophysical Research. - : American Geophysical Union (AGU). - 0148-0227 .- 2156-2202. ; 107:B7
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Journal article (peer-reviewed)
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5. |
- Magyari-Kope, B., et al.
(author)
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Low-temperature crystal structure of CaSiO3 perovskite : An ab initio total energy study
- 2002
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 65:19
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Journal article (peer-reviewed)abstract
- The stability of cubic CaSiO3 perovskite with respect to octahedral rotations is investigated by ab initio total-energy calculations. The proposed theoretical ground-state crystal structure has the orthorhombic Pbnm symmetry. Pressure gradually reduces the average tilting of the SiO6 octahedra relative to the cubic axis, from 7degrees at zero pressure to 4degrees at about 150 GPa. The energy difference between the orthorhombic and cubic phases at 0 GPa is 63 meV per f.u. and shows weak pressure dependence. A possible stabilization of the cubic phase at finite temperatures by entropy effects is discussed.
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6. |
- Magyari-Kope, B., et al.
(author)
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Model structure of perovskites : cubic-orthorhombic phase transition
- 2002
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In: Computational materials science. - 0927-0256 .- 1879-0801. ; 25:4, s. 615-621
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Journal article (peer-reviewed)abstract
- We extend the revised global parametrization method (revGPM) of orthorhombic perovskites with Pbnm symmetry to describe the changes in the lattice parameters and internal atomic coordinates within a broad range of structural distortions, including the vicinity of the orthorhombic-cubic phase transition. The applicability of the revGPM in the prediction of the evolution of the structural parameters under increasing hydrostatic pressure is demonstrated through test calculations performed for geophysically important perovskites. The present results are compared with the available theoretical and experimental data.
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8. |
- Magyari-Kope, B., et al.
(author)
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Origin of octahedral tilting in orthorhombic perovskites
- 2002
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:9
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Journal article (peer-reviewed)abstract
- The adopted crystal structure of the ABO(3) perovskites is determined by the balance between the interaction of the semicore states of the A and B atoms and oxygen ions. Topological considerations show that the structural setup always stabilizes the cubic phase at large pressures, while small or negative pressures favor nonvanishing octahedral tiltings. As an example, we show that the structural distortion in CaSiO3 perovskite is slightly depressed with hydrostatic pressure, but it increases significantly with increasing volume.
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