Ferroelectric control of superconductivity in an oxide interface*

We study the transport properties of two-dimensional (2D) interfaces between a (3D) ferroelectric oxide and a polar one. The interface is superconducting with a transition temperature of 300mK. From the analysis of the anisotropy of the critical fields we find that superconductivity is 2D in nature. The resistance and the Hall conductance of the interface exhibit a hysteretic behavior as a function of gate voltage. The area of the hysteresis loop becomes zero at the ferroelectric transition temperature. A hysteretic dependence on gate voltage is also seen for the superconducting transition temperature and critical fields. We discuss possible interplay between superconductivity and ferroelectricity at this interface.