Investigating Anomalous Thermal Expansion of Copper Halides by Inelastic Neutron Scattering and Ab-inito Phonon Calculations

Autor:	Gopakumar, Abhijith M., Gupta, M. K., Mittal, R., Rols, S., Chaplot, S. L.
Rok vydání:	2016
Předmět:	Condensed Matter - Materials Science
Zdroj:	Physical Chemistry Chemical Physics 19, 12107 (2017)
Druh dokumentu:	Working Paper
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:	arXiv
Externí odkaz:	http://arxiv.org/abs/1612.07068 Zobrazit plný text záznamu View this record from Arxiv