Electronic conductivity and structural distortion at the interface between insulators SrTiO3and LaAlO3

When insulator LaAlO3 is grown by epitaxy onto a TiO2-terminated (1001 surface of insulator SrTiO3, the system obtained has a metallic character. This phenomenon has been associated with an electrostatic frustration at the interface, as {100} surfaces of SrTiO3 are neutral while those of LaAlO3 are polar, but its microscopic mechanism is not quite understood. Here, we present a structural characterisation of this interface by aberration-corrected transmission electron microscopy. The unit cells at the interface appear elongated: we discuss this distortion in terms of electrostatic charge and extra carriers at the interface. (c) 2006 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.