Improved cationic stoichiometry and insulating behavior at the interface of LaAlO3/SrTiO3 formed at high oxygen pressure during pulsed-laser deposition
Artikel i vetenskaplig tidskrift, 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

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Författare

Alexei Kalaboukhov

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Y. A. Boikov

Russian Academy of Sciences

I.T. Serenkov

Russian Academy of Sciences

V.I. Sakharov

Russian Academy of Sciences

Johan Börjesson

Chalmers

Nikolina Tuzla

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Eva Olsson

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Dag Winkler

Chalmers, Mikroteknologi och nanovetenskap (MC2)

Tord Claeson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Europhysics Letters

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

Vol. 93 3

Ämneskategorier

Fysik

DOI

10.1209/0295-5075/93/37001

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Senast uppdaterat

2018-09-10