Atomic structure of the cassiterite SnO 2(111) surface

Abstract

We predict the relaxed (111) growth surface structure of cassiterite (rutile-structure SnO 2) by applying simple physical and chemical constraints. Experiments have shown that the surface symmetry is (1 × 1). We show that the simplest surface which is (1 × 1) and autocompensated has a single oxygen adatom per surface unit cell, located on the cell's mirror symmetry plane. The predicted relaxations of other surface atoms from their bulk positions are large enough to be detected by LEED analysis. This result demonstrates the power of the autocompensation principle, which straightforwardly shows that none of 63 possible truncated bulk structures should be stable, and points to the single-adatom stoichiometry.