Improved cationic stoichiometry and insulating behavior at the interface of LaAlO3/SrTiO3 formed at high oxygen pressure during pulsed-laser deposition
Journal article, 2011

Medium-energy ion spectroscopy, MEIS, and scanning transmission electron microscopy, STEM, were used to correlate the atomic structure of LaAlO3/SrTiO3 interfaces with their electrical properties. Interfaces were prepared at high (5x10(-2) mbar) and low (10(-4) mbar) oxygen pressure by pulsed-laser deposition. The high-oxygen-pressure heterostructures were insulating for all thicknesses while the low-oxygen-pressure ones became metallic for thicknesses above 4 unit cells. MEIS data show enhancement of the Sr surface peak and suppression of the La one in interfaces prepared at low oxygen pressure, which is interpreted as a La-Sr intermixing. The effect was considerably smaller in high-oxygen-pressure samples. Analysis of high-angle annular-dark-field STEM images of the LAO films also indicates intermixing between La and Sr in low-oxygen-pressure samples, supporting MEIS data. Our results reveal the important role of oxygen pressure on the formation of the interface electron gas. Copyright (C) EPLA, 2011



Alexei Kalaboukhov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Y. A. Boikov

Russian Academy of Sciences

I.T. Serenkov

Russian Academy of Sciences

V.I. Sakharov

Russian Academy of Sciences

Johan Börjesson


Nikolina Ljustina

Chalmers, Applied Physics, Microscopy and Microanalysis

Eva Olsson

Chalmers, Applied Physics, Microscopy and Microanalysis

Dag Winkler

Chalmers, Microtechnology and Nanoscience (MC2)

Tord Claeson

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Europhysics Letters

0295-5075 (ISSN) 1286-4854 (eISSN)

Vol. 93 3

Subject Categories

Physical Sciences



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