The atomic structure and vibrational states of the KTaO3(001) surface were investigated by means of density-functional calculations. In order to account for extended core states present in oxide perovskites, the full-potential linearized augmented plane-wave method was used. The (001) surface of KTaO3 was described using the slab super-cell approach. Computations were performed for various structural models which were considered in the light of the autocompensation principle and electron-counting rules. A low-energy structure was identified, for which the atomic positions were entirely relaxed with respect to the forces acting on the atoms. Surface vibrational modes were studied with the help of the frozen-phonon method. The investigations focused on providing an interpretation for the data obtained in helium-atom scattering experiments. The measurements revealed that the (001) surface of KTaO3 exhibited a higher-order reconstruction which exhibited surface vibrational features similar to those of the (1 x 1) surface.

Reconstruction of the (001) Surface of Potassium Tantalate. J.Fritsch, U.Schröder: Physica Status Solidi B, 1999, 215[1], 827-31