Issue
EPL
Volume 82, Number 1, April 2008
Article Number 17003
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/82/17003
Published online 05 March 2008
EPL, 82 (2008) 17003
DOI: 10.1209/0295-5075/82/17003

Electron energy loss spectroscopy determination of Ti oxidation state at the (001) LaAIO3/SrTiO3 interface as a function of LaAIO3 growth conditions

J.-L. Maurice1, G. Herranz1, C. Colliex2, I. Devos3, C. Carrétéro1, A. Barthélémy1, K. Bouzehouane1, S. Fusil1, D. Imhoff2, É. Jacquet1, F. Jomard4, D. Ballutaud4 and M. Basletic1

1  Unité mixte de physique CNRS/Thales and Université Paris-Sud-XI - Route départementale 128, 91767 Palaiseau cedex, France, EU
2  Laboratoire de physique des solides CNRS UMR8502, Université Paris-Sud-11 - 91405 Orsay cedex, France, EU
3  Institut d'électronique, de microélectronique et de nanotechnologie, Unité Mixte de Recherche CNRS 8520 avenue Poincaré, BP 69, 59652 Villeneuve d'Ascq cedex, France, EU
4  GEMaC-UMR 8635, CNRS - 1 place Aristide Briand, 92195 Meudon cedex, France, EU

jean-luc.maurice@thalesgroup.com

received 1 December 2007; accepted in final form 5 February 2008; published April 2008
published online 5 March 2008

Abstract
After the epitaxy of LaAlO3 on a TiO2-terminated {100} surface of SrTiO3, a high-mobility electron gas may appear, which has been the object of numerous works over the last four years. Its origin is a subject of debate between the interface polarity and unintended doping. Here we use electron energy loss "spectrum images", recorded in cross-section in a scanning transmission electron microscope, to analyse the Ti3+ ratio, characteristic of extra electrons. We find an interface concentration of Ti3+ that depends on growth conditions.

PACS
73.61.Ng - Insulators.
73.20.-r - Electron states at surfaces and interfaces.
79.20.Uv - Electron energy loss spectroscopy.

© EPLA 2008