Electronic densities of states of defect-free TiO2(110) and TiO2(001) surfaces

For defect-free Ti${\mathrm{O}}_2$(110) and Ti${\mathrm{O}}_2$(001) surfaces, we present wave-vector-resolved and -integrated surface electronic densities of states, obtained with the scattering theoretic method. The analysis of our results shows that the creation of these surfaces leads essentially to O $p$-derived resonances in the valence-band region and to Ti $d$-derived resonances in the conduction-band region. For both faces, the gap is found to be free of occupied surface states, in agreement with available ultraviolet photoelectron spectroscopy measurements.