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 (10.96eV). 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.