Off-Stoichiometry Driven Carrier Density Variation at the Interface of LaAlO/SrTiO.

The interface between LaAlO (LAO) and SrTiO (STO) has attracted enormous interests due to its rich physical phenomena, such as metallic nature, magnetism and superconductivity. In this work, we report our experimental investigations on the influence of the LAO stoichiometry to the metallic interface. Taking advantage of the oxide molecular beam epitaxy (MBE) technique, a series of high quality LAO films with different nominal La/Al ratios and LAO thicknesses were grown on the TiO-terminated STO substrates, where systematic variations of the LAO lattice constant and transport property were observed.