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TT: Fachverband Tiefe Temperaturen
TT 19: CE: Metal-Insulator Transition 2
TT 19.10: Talk
Wednesday, March 24, 2010, 12:15–12:30, H18
Possible localization of electrons at LaAlO3-SrTiO3 interfaces at finite temperatures — •Yang-Chung Liao1, Nicolas Reyren2, Stefano Gariglio2, Christoph Richter1, Rainer Jany1, Stefan Thiel1, Martin Breitschaft1, German Hammerl1, Thilo Kopp1, Jean-Marc Triscone2, and Jochen Mannhart1 — 1Experimental Physics VI, Center for Electronic Correlation and Magnetism, University of Augsburg, Augsburg, Germany — 2DPMC, University of Geneva, Geneva, Switzerland
Intriguingly, the LaAlO3-SrTiO3 (AlO2/LaO/TiO2/SrO) interface possesses conducting electrons if the LaAlO3 thickness exceeds 3 unit cells. By applying depleting gate fields in field-effect devices at finite temperatures, we observe the conducting interfaces to localize electrons. Below a critical carrier density, the interfaces display nonlinear current-voltage characteristics showing gap-like features. At higher carrier densities, the interface electron system is ohmic with a weak-localization type behavior. Based on current-voltage characteristics and magneto-transport properties, we trace the phase diagram of the LaAlO3-SrTiO3 interface electron system.