Comparative Hybrid Hartree-Fock-DFT Calculations of WO2-Terminated Cubic WO3 as Well as SrTiO3, BaTiO3, PbTiO3 and CaTiO3 (001) Surfaces

We performed, to the best of our knowledge, world’s first first-principles calculations for WO2-terminated cubic WO3 (001) surface and analyzed systematic trends in WO3, SrTiO3, BaTiO3, PbTiO3 CaTiO3 ab initio calculations. According principles calculations, all WO2 or TiO2-terminated CaZrO3 upper-layer atoms relax inwards towards crystal bulk, while second-layer upwards. The only two exceptions are outward relaxations layer O atoms. surface-band gaps at Γ–Γ point smaller than their respective bulk-band gaps. Ti–O chemical bond populations bulk those near surfaces. Conversely, W–O population is larger surface.