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| Naji, M. |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Kočí, Jan | Prague |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Dovesi, Roberto
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Topics
Publications (7/7 displayed)
- 2023Band gap, Jahn‐Teller deformation, octahedra rotation in transition metal perovskites LaTiO3$$ {}_3 $$citations
- 2022Effect of composition on the phonon softening in ABO3 - type perovskites: a DFT modellingcitations
- 2022The role of spin density for understanding the superexchange mechanism in transition metal ionic compounds. The case of KMF 3 (M = Mn, Fe, Co, Ni, Cu) perovskitescitations
- 2022How deeply are core electrons perturbed when valence electrons are spin polarized? The case study of transition metal compoundscitations
- 2021Phase transitions and superexchange mechanism in transition metal compounds. The case of KMnF 3 perovskitecitations
- 2018Experimental and Theoretical Infrared Signatures of REMO3 (RE = La, Pr, Nd, Sm, and M = Co, Fe) Perovskitescitations
- 2008B3LYP simulation of the full vibrational spectrum of 45S5bioactive silicate glass compared to nu-silicacitations
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article
Effect of composition on the phonon softening in ABO3 - type perovskites: a DFT modelling
Abstract
The evolution of the ferroelectric instability in ABO3 perovskites is systematically investigated for tantalates, niobates and titanates at the hybrid Density-Functional Theory level. The influence of the A cation is analysed in terms of the frequency of the lowest F1u IR-active phonon mode at different volumes for (Cs, Rb, K, Na)TaO3 , (Ba, Pb, Sn, Ge)TiO3 and (Rb, K, Na, Li)NbO3 and correlated with the ionic radius as well as the degree of hybridization in the bonds. The atomic displacement corresponding to each mode is described as a function of volume, and the static permittivity is calculated for the stable Pm¯3m phases. It is shown that the amplitude of the atomic displacements associated to the soft mode linked to the ferroelectric instability increases at a given volume when the ionic radius of the cation A decreases and when the hybridization of the B-O bond increases. This provides criteria for optimizing the dielectric properties of materials and for suggesting effective solid solutions. The tantalum perovskites presenting para-ferroelectric phase transitions, some of which close to ambient conditions, are interesting materials for high-permittivity dielectrics in view of lead-free compounds with high static dielectric response.