Superfluid stiffness renormalization and critical temperature enhancement in a composite superconductor

Abstract

We study a model of a composite system constructed from a "pairing layer" of disconnected attractive-U Hubbard sites that is coupled by single-particle tunneling, t_perp, to a disordered metallic layer. For small inter-layer tunneling the system is described by an effective long-range XY phase model whose critical temperature, T_c, is essentially insensitive to the disorder and is exponentially suppressed by quantum fluctuations. T_c reaches a maximum for intermediate values of t_perp, which we calculate using a combination of mean-field, classical and quantum Monte Carlo methods. The maximal T_c scales as a fraction of the zero temperature gap of the attractive sites when U is smaller than the metallic bandwidth, and is bounded by the maximal T_c of the two-dimensional attractive Hubbard model for large U. Our results indicate that a thin, rather than a thick, metallic coating is better suited for the enhancement of T_c at the surface of a phase fluctuating superconductor.

11 pages, 6 figures

References in corpus (7)

• High-temperature interface superconductivity between metallic and insulating cuprates
• Nature of the superconductor-insulator transition in disordered superconductors
• Theory of quantum metal to superconductor transitions in highly conducting systems
• A route to high temperature superconductivity in composite systems
• Enhancement of the superconducting transition temperature in La2-xSrxCuO4 bilayers: Role of pairing and phase stiffness
• Enhanced Superconductivity in Superlattices of High-$T_c$ Cuprates
• Enhancement of the superconducting transition temperature in cuprate heterostructures

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• Enhanced superconductivity via layer differentiation in trilayer Hubbard model
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