FIRST-PRINCIPLES CALCULATIONS OF THE CaF2(111), (110), AND (100) SURFACE ELECTRONIC AND BAND STRUCTURE

We present and discuss the results of calculations of the CaF2 bulk and surface electronic structure. Our results show, that the best agreement with experiment for the optical band gap (12.1 eV) can be obtained using a hybrid Hartree–Fock and density functional theory exchange functional, in which Hartree–Fock exchange is mixed with density functional theory exchange functionals, using Becke's three-parameter method, combined with the nonlocal correlation functionals by Perdew and Wang (10.96 eV). We also present calculations of CaF2(111), (110), and (100) surfaces. Our calculated surface energies confirm that the CaF2(111) surface is the most stable one, in agreement with the experiment.