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

Alexei Kalaboukhov (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; Y. A. Boikov ; I. T. Serenkov ; V. I. Sakharov ; J. Borjesson ; Nikolina Ljustina (Institutionen för teknisk fysik, Mikroskopi och mikroanalys) ; Eva Olsson (Institutionen för teknisk fysik, Mikroskopi och mikroanalys) ; Dag Winkler (Institutionen för mikroteknologi och nanovetenskap) ; Tord Claeson (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik)
EPL (0295-5075). Vol. 93 (2011), 3,
[Artikel, refereegranskad vetenskaplig]

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

Nyckelord: oxides

Denna post skapades 2011-03-21. Senast ändrad 2014-11-27.
CPL Pubid: 138198


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Institutioner (Chalmers)

Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik
Institutionen för teknisk fysik, Mikroskopi och mikroanalys (2005-2012)
Institutionen för mikroteknologi och nanovetenskap



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