The energetics and structure of rutile TiO2(110)

Density functional theory and a pseudopotential plane wave method are applied to study electronic and structural properties of the defect-free TiO2(110) surface. The variations of the surface energy, work function, and atomic displacements are examined for partially and fully relaxed slabs modelling the rutile (110) surface, and consisting of up to 33 atomic layers. Relatively small relaxations of atomic positions in the outermost layers have a strong influence on the calculated surface energies and work functions. The effect of nonequivalence of the odd-even layer terminations is explored. A simple method is proposed which allows one to estimate accurate surface energies for relaxed systems from calculations for partially relaxed slabs.