First-principles study of structural, elastic, and bonding properties of pyrochlores.

Pruneda, J. M. and Artacho, E. (2005) First-principles study of structural, elastic, and bonding properties of pyrochlores. Physical Review B, 72. Art. No. 085107. DOI 10.1103/PhysRevB.72.085107

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Abstract

Density Functional Theory calculations have been performed to obtain lattice parameters, elastic constants, and electronic properties of ideal pyrochlores with the composition A2B2O7 (where A=La,Y and B=Ti,Sn,Hf, Zr). Some thermal properties are also inferred from the elastic properties. A decrease of the sound velocity (and thus, of the Debye temperature) with the atomic mass of the B ion is observed. Static and dynamical atomic charges are obtained to quantify the degree of covalency/ionicity. A large anomalous contribution to the dynamical charge is observed for Hf, Zr, and specially for Ti. It is attributed to the hybridization between occupied 2p states of oxygen and unoccupied d states of the B cation. The analysis based on Mulliken population and deformation charge integrated in the Voronoi polyhedra indicates that the ionicity of these pyrochlores increases in the order Sn–Ti–Hf–Zr. The charge deformation contour plots support this assignment.

Item Type: Article
Uncontrolled Keywords: 2005 AREP 2005 P IA49
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Physical Review B
Volume: 72
Page Range: Art. No. 085107
Identification Number: 10.1103/PhysRevB.72.085107
Depositing User: Sarah Humbert
Date Deposited: 19 Aug 2010 09:36
Last Modified: 23 Jul 2013 09:59
URI: http://eprints.esc.cam.ac.uk/id/eprint/1786

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