Ni ultrathin film development on SrTiO3(1 0 0) surface

The Ni ultrathin film development on the SrTiO3(1 0 0) surface doped by Fe acceptors (0.14 wt%) has been studied by AES, LEED, TDS, EELS and relative WF measurements. Heating of the clean STO surface above 1100 K causes TiO desorption. The adsorbate grows in the simultaneous multilayers (SM) mode, approaching a rather metallic character at high coverages. The nickel adatoms in the metal–oxide interface, interact with the outmost surface oxygen atoms resulting in a two-dimensional NiO compound. The formation of this surface oxide is: (i) time dependent, (ii) temperature independent for T>300 K and (iii) promoted by the presence of surface defects. A significant amount of Ni (≅1.4 ML) remains on the surface, strongly chemisorbed, after high temperature annealing.