Engineering interfaces in cuprate superconductors

Using an advanced molecular beam epitaxy system for atomic-layer engineering of complex oxides, we have fabricated a variety of superlattices with stacked layers of La2-xSrxCuO4 doped to different levels. In superlattices formed by stacking highly overdoped, metallic La1.5Sr0.5CuO4 and insulating La2CuO4 layers we have observed superconductivity at temperature as high as 30 K, even though neither of the building blocks was superconducting. Different possible mechanisms of this superconductivity are discussed. (C) 2007 Elsevier B.V. All rights reserved.