Ground state and lattice dynamical study of ionic conductors CaF2, SrF2 and BaF2 using density functional theory

The present paper reports a comprehensive and complementary study on structural, electronic and phonon properties of face centered cubic fluorites, namely CaF2, BaF2 and SrF2, using first principles density functional calculations within the generalized gradient approximation. The calculated lattice constants and bulk modulus are in good agreement with available experimental data. The analysis of band structure and density of states confirms the ionic character for all the three fluorides. The phonon dispersion curves and corresponding phonon density of states obtained in the present work are consistent with the available experimental and other theoretical data. The LO–TO splitting is maximum for CaF2, which confirms that the ionicity is maximum in the case of CaF2. The phonon properties for SrF2 have been calculated for the first time.

Using first principles density functional theoretical calculations a comprehensive study on structural, electronic and phonon properties of face centered cubic fluorites namely CaF2, BaF2 and SrF2 have been performed. All three fluorides have ionic character along alkali-florine (X-F) direction found with the analysis of band structure, density of states and charge density plot. Figure optionsDownload as PowerPoint slideHighlights
► Ground state and lattice dynamical study of ionic conductors CaF2, SrF2 and BaF2.
► Predicted the band structure, phonon dispersion curves and corresponding phonon density of states.
► LO–TO splitting is maximum for CaF2, which confirms that the ionicity is maximum in the case of CaF2.
► These compounds have an indirect band gap.