Sumithra, S. ; Waghmare, U. V. ; Umarji, A. M. (2007) Anomalous dynamical charges, phonons, and the origin of negative thermal expansion in Y2W3O12 Physical Review B: Condensed Matter and Materials Physics, 76 (2). 024307_1-024307_5. ISSN 1098-0121
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Official URL: http://prb.aps.org/abstract/PRB/v76/i2/e024307
Related URL: http://dx.doi.org/10.1103/PhysRevB.76.024307
Abstract
We use a combination of classical model and first-principles density functional theory calculations to study lattice dynamics of Y2W3O12 and identify phonons responsible for its negative thermal expansion (NTE). Born dynamical charges of various atoms are found to deviate anomalously from their nominal values. We find that the phonons with energy from 4 to 10 meV are the primary contributors to its NTE. These phonons involve rotations of the YO6 octahedra and WO4 tetrahedra in mutually opposite sense and collective translational atomic displacements, reflecting a strong mixing between acoustic and optic modes.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to The American Physical Society. |
| ID Code: | 59396 |
| Deposited On: | 06 Sep 2011 05:31 |
| Last Modified: | 06 Sep 2011 05:31 |
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