Fabrication quasi-two-dimensional conducting area and superconductivity at the ferroelectric/dielectric interfaces

Abstract

We present the results of the investigations of high conducting area and superconductivity at the interfaces between ferroelectric oxide and insulating oxide in heterostructures, isostructural to BaTiO3/LaMnO3 and BaTiO3/La2CuO4. The numerical simulations of these heterostructures have been performed. The temperature dependence of the measured electrical resistance of Ba0.8Sr0.2TiO3/LaMnO3 (BSTO/LMO) is compared to that exhibited by LaMnO3 (LMO) single crystals without the films. It is found that in the samples with the film, for which the axis of polarization in the ferroelectric is directed along the normal to the surface of the single crystal, the electrical resistance decreases significantly with temperature, exhibiting metallic behavior at low temperatures. The transition to the state with 2DEG at the interface is demonstrated. The effect of a magnetic field on heterostructure BSTO/LMO haves been investigated. It is shown that magnetic field changes strongly the resistivity of the interface BSTO/LMO. We study properties of the interface of the heterostructure Ba0.8Sr0.2TiO3/La2CuO4 and found the superconducting behavior with transition temperature Tc about 30 K. The proposed concept promises the ferroelectrically controlled interface conductivity and superconductivity. All this offers the possibility to design novel electronic devices.