  Recently, it was established that a two-dimensional electron system can arise
at the interface between two oxide insulators LaAlO3 and SrTiO3. This
paradigmatic example exhibits metallic behaviour and magnetic properties
between non-magnetic and insulating oxides. Despite a huge amount of
theoretical and experimental work a thorough understanding has yet to be
achieved. We analyzed the structural deformations of a LaAlO3 (001) slab
induced by hydrogen ad-atoms and oxygen vacancies at its surface by means of
density functional theory. Moreover, we investigated the influence of surface
reconstruction on the density of states and determined the change of the local
density of states at the Fermi level with increasing distance from the surface
for bare LaAlO3 and for a conducting LaAlO3/SrTiO3 interface. In addition, the
Al-atom displacements and distortions of the TiO6-octahedra were estimated.
