Regensburg 2010 – scientific programme

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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.