Investigating anomalous thermal expansion of copper halides by inelastic neutron scattering and ab initio phonon calculations
| Autor: | M. K. Gupta, S. L. Chaplot, R. Mittal, Stéphane Rols, Abhijith Gopakumar |
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| Rok vydání: | 2017 |
| Předmět: |
Condensed Matter - Materials Science
Materials science Phonon Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences General Physics and Astronomy chemistry.chemical_element Halide 02 engineering and technology Inelastic scattering 021001 nanoscience & nanotechnology 01 natural sciences Copper Molecular physics Thermal expansion Inelastic neutron scattering Condensed Matter::Materials Science Negative thermal expansion chemistry 0103 physical sciences Neutron Physical and Theoretical Chemistry 010306 general physics 0210 nano-technology |
| Zdroj: | Physical Chemistry Chemical Physics. 19:12107-12116 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/c7cp01517h |
| Popis: | We investigate detailed lattice dynamics of copper halides CuX (X=Cl, Br, I) using neutron inelastic scattering measurements and ab-initio calculations aimed at a comparative study of their thermal expansion behavior. We identify the low energy phonons which soften with pressure and are responsible for negative thermal expansion. The eigenvector analysis of these modes suggests that softening of the transverse-acoustic modes would lead to NTE in these compounds. The calculations are in very good agreement with our measurements of phonon spectra and thermal expansion behavior as reported in the literature. Our calculations at high pressure further reveal that large difference in negative thermal expansion behavior in these compounds is associated with the difference of the unit cell volume. Comment: 23 Pages, 14 Figures, 3 Tables |
| Databáze: | OpenAIRE |
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