Electronic conductivity and structural distortion at the interface between insulators SrTiO₃ and LaAlO₃

When insulator LaAlO 3 is grown by epitaxy onto a TiO 2 ‐terminated {100} surface of insulator SrTiO 3 , the system obtained has a metallic character. This phenomenon has been associated with an electrostatic frustration at the interface, as {100} surfaces of SrTiO 3 are neutral while those of LaAlO 3 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. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)