Electron energy loss spectroscopy determination of Ti oxidation state at the (001) LaAlO3/SrTiO3 interface as a function of LaAlO3 growth conditions

• Published in: Europhysics letters Vol. 82; no. 1; pp. 17003 - 17003/6
• Main Authors: Maurice, J L, Herranz, G, Colliex, C, Devos, I, Carretero, C, Barthelemy, A, Bouzehouane, K, Fusil, S, Imhoff, D, Jacquet, E, Jomard, F, Ballutaud, D, Basletic, M
• Format: Journal Article
• Language: English
• Published: European Physical Society / EDP Sciences / Società Italiana di Fisica / IOP Publishing 01.04.2008
• Subjects: Condensed Matter; Materials Science; Physics; Electron states at surfaces and interfaces; Electron energy loss spectroscopy; Electrical properties of specific thin films: insulators
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/0295-5075/82/17003

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.