Ab initio study on structure and phase transition of A- and B-type rare-earth sesquioxides Ln{sub 2}O{sub 3} (Ln=La-Lu, Y, and Sc) based on density function theory
- College of Materials Science and Engineering, Fuzhou University, University Park, 350108 Fuzhou (China)
- Max-Planck-Institut fuer Metallforschung und Institut fuer Nichtmetallische Anorganische Materialien der Universitaet Stuttgart, Heisenbergstrasse 3, 70569 Stuttgart (Germany)
Ab initio energetic calculations based on the density functional theory (DFT) and projector augmented wave (PAW) pseudo-potentials method were performanced to determine the crystal structural parameters and phase transition data of the polymorphic rare-earth sesquioxides Ln{sub 2}O{sub 3} (where Ln=La-Lu, Y, and Sc) with A-type (hexagonal) and B-type (monoclinic) configurations at ground state. The calculated results agree well with the limited experimental data and the critically assessed results. A set of systematic and self-consistent crystal structural parameters, energies and pressures of the phase transition were established for the whole series of the A- and B-type rare-earth sesquioxides Ln{sub 2}O{sub 3}. With the increase of the atomic number, the ionic radii of rare-earth elements Ln and the volumes of the sesquioxides Ln{sub 2}O{sub 3} reflect the so-called 'lanthanide contraction'. With the increase of the Ln{sup 3+}-cation radius, the bulk modulus of Ln{sub 2}O{sub 3} decreases and the polymorphic structures show a degenerative tendency. - Graphical abstract: This graph shows the calculated transition pressure with respect to the transition of the Ln{sub 2}O{sub 3} from its B- to A-type together with the available experimental data superimposed. The transition pressure was obtained by calculating the common tangent slope of the two fitted E-V curves based on the empirical third-order Birch-Murnaghan equation of state.
- OSTI ID:
- 21043753
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 11; Other Information: DOI: 10.1016/j.jssc.2007.09.022; PII: S0022-4596(07)00385-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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