Dresden 2006 – scientific programme

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SYMM: Multi-ferroic materials

SYMM 1: Multiferroic Materials - Theory

SYMM 1.2: Invited Talk

Tuesday, March 28, 2006, 15:00–15:30, HSZ 04

Electrostatic Interface Tuning in Superconducting Oxide Heterostructures — •N. Pavlenko — Institute of Physics, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany

In oxide heterostructures consisting of high-temperature superconducting films and ferroelectric/dielectric layers, electric fields can be used to switch between superconducting and insulating states by electrostatically tuning the free carrier density. Analyzing the superconducting pairing in a cuprate film in terms of a developed microscopic model model, we show that a coupling to electric dipoles and phonons at the interface of film and dielectric/ferroelectric gate localizes the injected charge and leads to a superconductor-insulator transition [N. Pavlenko et al., Phys. Rev. B, 72 (2005) 174516]. We find that in the correlated oxide films, the strong interface polaron effect is inherently connected to the stabilization of interface charge orderings and inhomogeneous states. This leads to a dramatic modification of the doping dependent phase diagrams which is expected to shed light on recent electric field-effect experiments with HTSC cuprates. Based on these results, we consider several novel design concepts for superconducting field-effect devices [N. Pavlenko, Phys. Rev. B 70 (2004) 094519; N. Pavlenko et al., Appl. Phys. Lett. 70 (2005) 012507] and discuss the ways to amplify the electric field effect.