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

The microscopic structure and energetics of a SrTiO3 (001) surface covered with thin layers of Pd have been investigated by means of ab-initio electro nic-structure calculations. A mixed-basis pseudopotential technique based o n the local density functional theory was employed. Supercells containing S rTiO3 substrate slabs, with either SrO or TiO2 surface terminations, and Pd films of varying thicknesses were used to model the free (001) surfaces an d the (001) heterophase interfaces. Based on the calculated energetics of a dhesion for the different interfaces, the microscopic energetics of wetting and layer growth has been analysed. The TiO2 terminated substrate is energ etically favourable for the adhesion of Pd films, with the Pd atoms bonded on top of the O atoms. The film adhesion is strongest for one (001) layer o f fcc Pd and becomes weaker with increasing film thickness.