Eur. Phys. J. B (2017) 90: 57
https://doi.org/10.1140/epjb/e2017-70487-y

Regular Article

First principles study of the vibrational, dielectric and thermal properties of SrClF

¹ School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471023, P.R. China
² Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900, P.R. China

^a e-mail: zhenlonglv@foxmail.com

Received: 19 August 2016
Received in final form: 15 December 2016
Published online: 27 March 2017

Abstract

SrClF is an important optical crystal and has many technological applications. In this work, vibrational, dielectric and thermal properties of SrClF were investigated by density functional perturbation calculation. The calculated Born effective charges are close to their nominal ionic charges, revealing the ionic characteristic of SrClF. Group theory analysis indicates that there are two E_u and A_2u infrared modes at the Brillouin zone center of SrClF. The LO-TO splitting of these infrared modes were calculated and discussed and their vibrational modes were sketched. Static dielectric constants were studied, which show that SrClF has a larger ionic dielectric contribution than its electrons. Its birefringence was calculated and the infrared reflectance spectra were simulated, which can be used to explain the experimental findings. Based on the computed phonon dispersion curves, the lattice heat capacity, the Grüneisen parameter and the thermal expansion coefficient as functions of temperature were predicted.