Computational study of charge accumulation at SnO2(1Â 1Â 0) surface

Features of SnO2(1 1 0) surfaces with a surplus electron are considered computationally by applying density functional method. The additional charge is found to influence on surface energetics and surface relaxations considerably with respect to the corresponding surfaces without additional charge. This effect is pronounced in the cases of oxidized surfaces, where different oxygen adsorbates (O, O2 and O3) tend to capture the charge. On stoichiometric surface, these oxygen species are adsorbed on-top of the five-fold coordinated surface tin atoms and are attributed to adsorbed O−, O2- and O3- species associated with spin polarization. Based on evaluated total energy differences formation of these species are compared. In cases of stoichiometric and slightly oxygen deficient surfaces without adsorbates, charge accumulation is qualitatively similar to the case of bulk SnO2 with a considerable amount of the surplus charge enriched around Sn atoms. A pronounced charge accumulation is observed around under-coordinated surface tin atoms of stoichiometric and oxygen deficient (1 1 0) surfaces.