Microscopic structure and bonding at the Pd/SrTiO3 (001) Interface an ab-initio local-density-functional study

Abstract

The microscopic structure and energetics of a SrTiO3 (001) surface covered with thin layers of Pd have been investigated by means of ab-initio electronic-structure calculations. A mixed-basis pseudopotential technique based on the local density functional theory was employed. Supercells containing SrTiO3 substrate slabs,with either SrO or TiO2 surface terminations, and Pd films of varying thicknesses were used to model the free (001) surfaces and the (001) heterophase interfaces. Based on the calculated energetics of adhesion for the different interfaces, the microscopic energetics of wetting and layer growth has been analysed. The TiO2 terminated substrate is energetically favourable for the adhesion of Pd films, with the Pdatoms bonded on top of the O atoms. The film adhesion is strongest for one (001) layer of fcc Pd and becomes weaker with increasing film thickness.