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

Jean-Luc Maurice (1) , C. Carretero (1) , Marie-José Casanove (2) , K. Bouzehouane (1) , S. Guyard (1) , É. Larquet (3) , J.-P. Contour (1)

1 Laboratoire Albert Fert (ex-UMPhy Unité mixte de physique CNRS/Thales)
2 CEMES - Centre d'élaboration de matériaux et d'études structurales
3 IMPMC - Institut de minéralogie et de physique des milieux condensés

When insulator LaAlO3 is grown by epitaxy onto a TiO2-terminated {100} surface of insulator SrTiO3, the resulting system 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 in-terface by spherical aberration-corrected transmission electron microscopy. We show that the unit cells at the interface are elongated along the growth direction, and interpret this distortion in terms of Jahn-Teller effect.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Electrons fortement corrélés [cond-mat.str-el]

Jean-Luc Maurice, C. Carretero, Marie-José Casanove, K. Bouzehouane, S. Guyard, et al.. Electronic conductivity and structural distortion at the interface between insulators SrTiO3 and LaAlO3. 2005. ⟨hal-00013281v1⟩