Electronic structure of the R2Ti2O7 (R = Sm-Er, Yb, Lu) oxides - art. no. 075106

We present the results of the electronic structure investigation for the co mpounds R2Ti2O7 (R = Sm-Er, Yb, Lu) with the pyrochlore-type crystal struct ure. The methods of x-ray photoelectron and emission spectroscopies, as wel l as the first-principles band-structure calculations have been employed. A good agreement between theoretical and experimental results was observed. We found considerable influence of the R 5p - O 2s interaction on the forma tion of the subvalent bands that has to be taken into account while interpr eting experimental data. Estimated values of the optical gaps are closely r elated to the degree of TiO6 octahedron distortion.