| Autor: |
Alfredsson, M., Brodholt, J. P., Wilson, P. B., Price, G. D., Corà, F., Calleja, M., Bruin, R., Blanshard, L. J., Tyer, R. P. |
| Předmět: |
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| Zdroj: |
Molecular Simulation; Apr2005, Vol. 31 Issue 5, p367-377, 11p |
| Abstrakt: |
We present the structural as well as elastic properties of the alkaline earth oxides and FeO, calculated using hybrid exchange functionals within DFT. We show that by empirically fitting the amount of Fock-exchange in the hybrid functionals, we can accurately reproduce the pressure-induced phase transitions for MgO, CaO, SrO and BaO. For FeO the hybrid functionals predict an insulator?metal transition at ca. 150?GPa, associated with an i-B8?B8 structural phase transition. The structural phase transition is accompanied by a spin transition from a high- to low-spin electron configuration on the Fe 2+ ions. Hence, FeO undergoes a magnetic phase transition from an anti-ferromagnetic to non-magnetic structure. We also find that as the ionicity of the polymorphs increases a higher fraction of Fock-exchange is required to reproduce the structural volumes reported from experiments. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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