Jean-Marc Triscone
Department of Condensed Matter Physics, University of Geneva, Switzerland
Date
9 April 2008
Title
Superconducting Interfaces between Insulating Oxides
Abstract
At interfaces between complex oxides, electronic systems with unusual properties can be generated. As reported first by Ohtomo and Hwang, a highly mobile electron gas is formed at the interface between LaAlO3 and SrTiO3, two insulating dielectric perovskite oxides. It will be shown that the ground state of this system is superconducting. The superconducting critical temperature is about 200mK. The characteristics of the observed superconducting transitions are consistent with a 2-dimensional superconducting sheet as thin as a few nm. The field effect allows the normal state and superconducting state properties of this electron gas to be spectacularly controlled. In particular, the electric field allows the critical temperature to be tuned between 200mK and zero and the phase diagram to be mapped revealing a superconductor to insulator transition.