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

Abstract

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.

23 Pages, 14 Figures, 3 Tables

References in corpus (3)

• Phonon Properties, Thermal Expansion, and Thermomechanics of Silicene and Germanene
• Anomalous thermal conductivity and suppression of negative thermal expansion in ScF3
• Lattice Dynamics and Thermal Expansion Behavior in Metal Cyanides, MCN (M=Cu, Ag, Au): Neutron Inelastic Scattering and First Principles Calculations

Cited by in corpus (2)

• Determination of acoustic phonon anharmonicities via second-order Raman scattering in CuI
• Phonons and Anomalous Thermal Expansion Behaviour in Crystalline Solids