Enhancement of the Superconducting Transition Temperature ofLa2−xSrxCuO4Bilayers: Role of Pairing and Phase Stiffness

Abstract

The superconducting transition temperature T(c) of bilayers comprising underdoped La(2-x)Sr(x)CuO(4) films capped by a thin heavily overdoped metallic La(1.65)Sr(0.35)CuO(4) layer, is found to increase with respect to T(c) of the bare underdoped films. The highest T(c) is achieved for x=0.12, close to the "anomalous" 1/8 doping level, and exceeds that of the optimally doped bare film. Our data suggest that the enhanced superconductivity is confined to the interface between the layers. We attribute the effect to a combination of the high pairing scale in the underdoped layer with an enhanced phase stiffness induced by the overdoped film.

Anomalous expansion of the copper-apical-oxygen distance in superconducting cuprate bilayers

“…Another recent discovery of interface superconductivity in complex oxides (1)(2)(3)(4)(5) has also generated some excitement and triggered a debate about its origin and the possibility to enhance T c further (6)(7)(8)(9). The interfacial enhancement (3) of T c is influenced by the crystal structure.…”

Emergent phenomena at oxide interfaces

“…These materials are on either side of the high temperature superconducting "dome" of the T c vs. doping curve, but via charge transfer, superconductivity is found just at the interface. 15,16 It has been suggested that such a separation of a region of strong pairing potential, and a region of high superfluid density, may be an avenue to enhancing T c at interfaces. 17,18 …”

Structural andTcinhomogeneities inherent to doping inLa2−xSrxMosqueira1, Cabo2, Vidal3 2009Phys. Rev. B2811670View full textAdd to dashboardCite

“…4,[16][17][18][19][20][21][22][23][24][25][26] Nevertheless, these authors propose very different origins for such anomalous precursor diamagnetism, including the presence of superconducting phase fluctuations up to the pseudogap temperature or the existence in the bulk of intrinsic inhomogeneities with short characteristic lengths, as those observed by using surface probes.…”