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Negative thermal expansion properties in tetragonal NbPO5 from the first principles studies

Authors :
Tao Li
Xiaonan Fu
Dahu Chang
Qiang Sun
Fei Wang
Source :
AIP Advances, Vol 7, Iss 3, Pp 035202-035202-8 (2017)
Publication Year :
2017
Publisher :
AIP Publishing LLC, 2017.

Abstract

By using the first-principles calculations based on density functional theory combined with quasi-harmonic approximation, we have studied the geometric structural, thermal properties, and the negative thermal expansion (NTE) properties of tetrahedral NbPO5. The variations of cell parameter and cell volume of tetrahedral NbPO5 with temperature show that it displays NTE behavior in the range of 473-800 K along a-axis and the corresponding average coefficient of thermal expansion (CTE) is approximately -0.766 ×10−6 K−1, while the c cell parameter and the cell volume display positive thermal expansion behaviors. These results are in consistent well with the experiment observations. Further vibrational modes analysis, together with Grüneisen parameters calculations, revealed that the transverse vibration of O corner atoms accompanying the rocking motions of corner-shared NbO6 octahedron and PO4 tetrahedron dominate the negative thermal properties of tetrahedral NbPO5. Our findings will provide an understanding for the underlying mechanisms of the NTE in oxides materials.

Subjects

Subjects :
Physics
QC1-999

Details

Language :
English
ISSN :
21583226
Volume :
7
Issue :
3
Database :
Directory of Open Access Journals
Journal :
AIP Advances
Publication Type :
Academic Journal
Accession number :
edsdoj.83c4616f899a4b4ab6e2749ef3d5f34c
Document Type :
article
Full Text :
https://doi.org/10.1063/1.4977874