Influence of mechanical stresses on the charge state of the interface in the LaAlO₃/(001)SrTiO₃ heterostructures with a distorted stoichiometry

The medium-energy ion scattering (MEIS) spectroscopy was used to obtain the data on the structure and stoichiometry of interfaces in LaAlO₃/SrTiO₃ (LAO/STO) heterostructures. The coverage of the LAO/STO heterostructure with a LAO film increased by a factor of almost two as the lanthanum aluminate layer thickness increased from 1 to 6 unit cells. It is shown that the formation of the heterostructure is accompanied by the interchange with Sr ions of the substrate and La ions of the firm. The influence of the oxygen pressure on the formation of the heterostructure has been studied. The conditions required to form nanodimentional interlayer of a quasi-two-dimensional electron gas with high mobility of electrons in the interface region are analyzed.