Electronic properties of CaF₂ bulk and interfaces

The electronic band structures of ultra-wide gap CaF 2 are investigated with both the hybrid functional and efficient generalized gradient approximation (GGA) + U scheme. scheme is in excellent agreement experiments, while introducing an on-site Coulomb interaction to F-2p orbitals also accurately reproduces experimental bandgap greatly improves previous theoretical results using advanced structure schemes. We apply GGA method study /Si metal/CaF interfaces. insulating interfaces a clear built based on electron counting rule. Our supercell calculations show type-II alignment valence offset follows descending trend from (001) (111) then (110). calculation convergence further tested metallic contacts. observed be weakly pinned different orientations sharing similar pinning factor S up ∼0.9, owing highly ionic nature . approach proven useful tool studying such fluoride