Structural phase stability of CaF < inf > 2 < /inf > and SrF < inf > 2 < /inf > under pressure

Abstract

The electronic band structure of CaF2 and SrF2 was calculated in the fluorite and orthorhombic phases. The calculations were performed using tight binding linear muffin tin orbital method. The calculated ground state properties are in fairly good agreement with the experimental results. The transition pressure of CaF2 and SrF2 was found to be 9.1 and 7GPa, respectively. The calculated transition pressures of CaF2 are in good agreement with the experimental results. These systems were found to be wide band gap insulators with the band gap initially increasing with pressure, which decreases upon further compression. CaF2 and SrF2 are predicted to undergo metallization around 210 and 92GPa, respectively. The possible reason for the metallization was also discussed. © 2002 Elsevier Science B.V. All rights reserved.