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arXiv · 1510.00361

The negative thermal expansion mechanism of zirconium tungstate, ZrW2O8

Leila H. N. Rimmer·Martin T. Dove·Keith Refson
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Abstract

Negative thermal expansion in ZrW2O8 was investigated using a flexibility analysis of ab-initio phonons. It was shown that no previously proposed mechanism adequately describes the atomic-scale origin of negative thermal expansion in this material. Instead it was found that NTE in ZrW2O8 is driven, not by a single mechanism, but by wide bands of phonons that resemble vibrations of near-rigid WO4 units and Zr-O bonds at low frequency, with deformation of O-W-O and O-Zr-O bond angles steadily increasing with increasing NTE phonon frequency. It is asserted that this phenomenon is likely to provide a more accurate explanation for NTE in many complex systems not yet studied.

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Leila H. N. Rimmer, Martin T. Dove, Keith Refson. 2016-02-16. The negative thermal expansion mechanism of zirconium tungstate, ZrW2O8. https://arxiv.org/abs/1510.00361

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