Ekaterina I. Marchenko, Artem R. Oganov, Efim A. Mazhnik, Nikolay N. Eremin
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引用次数: 2
Abstract
Using the evolutionary crystal structure prediction algorithm USPEX, we showed that at pressures of the Earth’s lower mantle (24-136 GPa) CaAl2O4 is the only stable calcium aluminate. At pressures above 7.0 GPa it has the CaFe2O4-type structure with space group Pnma. This phase is one of the prime candidate aluminous phases in the lower mantle of the Earth. We show that at low pressures 5CaO • 3Al2O3 (C5A3) with space group Cmc21, CaAl4O7 (with space group C2/c) and CaAl2O4 (space group P21/m) are stable at pressures of up to 2.1, 1.8 and 7.0 GPa, respectively. The previously unknown structure of the orthorhombic "CA-III" phase is also found in our calculations. This phase is metastable at 0 K and has a layered structure with space group P21212.
期刊介绍：
Physics and Chemistry of Minerals is an international journal devoted to publishing articles and short communications of physical or chemical studies on minerals or solids related to minerals. The aim of the journal is to support competent interdisciplinary work in mineralogy and physics or chemistry. Particular emphasis is placed on applications of modern techniques or new theories and models to interpret atomic structures and physical or chemical properties of minerals. Some subjects of interest are:
-Relationships between atomic structure and crystalline state (structures of various states, crystal energies, crystal growth, thermodynamic studies, phase transformations, solid solution, exsolution phenomena, etc.)
-General solid state spectroscopy (ultraviolet, visible, infrared, Raman, ESCA, luminescence, X-ray, electron paramagnetic resonance, nuclear magnetic resonance, gamma ray resonance, etc.)
-Experimental and theoretical analysis of chemical bonding in minerals (application of crystal field, molecular orbital, band theories, etc.)
-Physical properties (magnetic, mechanical, electric, optical, thermodynamic, etc.)
-Relations between thermal expansion, compressibility, elastic constants, and fundamental properties of atomic structure, particularly as applied to geophysical problems
-Electron microscopy in support of physical and chemical studies
-Computational methods in the study of the structure and properties of minerals
-Mineral surfaces (experimental methods, structure and properties)
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