Electronic structure of the interfacial LaAlO$_3$/SrTiO$_3$ 2D electron gas

The interface between LaAlO$_3$ and SrTiO$_3$, two good band insulators, was found in 2004 to be conducting with a high mobility [1] and, in some doping range, superconducting with a maximum critical temperature of about 200~mK [2,3]. I will describe recent experiments aiming at determining the origin of the electron gas. I will then discuss the transport properties of high mobility samples that display Shubnikov de Haas (SdH) oscillations [4]. In such high mobility samples, electric field tuning of the carrier density allows the electronic structure to be followed through analysis of the evolution of the SdH oscillations. \\[4pt] [1] A. Ohtomo, H. Y. Hwang, Nature 427, 423 (2004).\\[0pt] [2] N. Reyren, S. Thiel, A. D. Caviglia, L. Fitting Kourkoutis, G. Hammerl, C. Richter, C. W. Schneider, T. Kopp, A.-S. Ruetschi, D. Jaccard, M. Gabay, D. A. Muller, J.-M. Triscone and J. Mannhart, Science 317, 1196 (2007).\\[0pt] [3] A. Caviglia, S. Gariglio, N. Reyren, D. Jaccard, T. Schneider, M. Gabay, S. Thiel, G. Hammerl, J. Mannhart, and J.-M. Triscone, Nature 456, 624 (2008).\\[0pt] [4] A.D. Caviglia, S. Gariglio, C. Cancellieri, B. Sac\'ep\'e, A. F\^ete, N. Reyren, M. Gabay, A.F. Morpurgo, J.-M. Triscone, Physical Review Letters 105, 236802 (2010).