Enhancement of superconducting stiffness in hybrid superconducting-metallic bilayers

Fuente: arXiv
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Main Authors: Ebot, J. E., Pizzino, Lorenzo, Mardazad, Sam, Hofmann, Johannes S., Giamarchi, Thierry, Kantian, Adrian
Format: Preprint
Published: 2026
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author Ebot, J. E.
Pizzino, Lorenzo
Mardazad, Sam
Hofmann, Johannes S.
Giamarchi, Thierry
Kantian, Adrian
author_facet Ebot, J. E.
Pizzino, Lorenzo
Mardazad, Sam
Hofmann, Johannes S.
Giamarchi, Thierry
Kantian, Adrian
contents Boosting superconductivity by metallic reservoirs is the essence of Kivelson's bilayer proposal. One layer provides pairing to the electrons, while the weakly coupled metal provides additional phase coherence to those pairs by mediating extended-range pair-pair coupling. Demonstrating significant and unambiguous performance gains with strong-coupling methods for such set-ups had been difficult. In the present work, we study these systems doped away from half-filling, corresponding to a partially spin-polarized 1D Anderson- or Kondo-lattice. We show that this breaks the coexistence of dominant superconducting and density-density correlations decisively in favour or the former. Consequently, we provide evidence that in this doped regime, superconducting near-long-range order is not precluded by a small charge-gap in the thermodynamic limit, as we have recently shown to be the case at half-filling [JE Ebot $et$ $al.$, arXiv:2602.11153 [cond-mat.supr-con]]. We study the complex manner in which the enhancement of superconductivity in the pairing layer depends on the parameters of the metal, and especially that both pairing-limited and stiffness-limited regimes may appear in these systems. In addition to superconducting bilayers, our results are relevant, via a particle-hole transformation, for heavy-fermion Kondo-lattice materials in magnetic fields, as we provide previously lacking insight on the competition between antiferromagnetic and easy-plane magnetism, as well as a route for comprehensive indirect tests of Kivelson's bilayer proposal well beyond previous capabilities.
format Preprint
id arxiv_https___arxiv_org_abs_2604_28187
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Enhancement of superconducting stiffness in hybrid superconducting-metallic bilayers
Ebot, J. E.
Pizzino, Lorenzo
Mardazad, Sam
Hofmann, Johannes S.
Giamarchi, Thierry
Kantian, Adrian
Superconductivity
Quantum Gases
Strongly Correlated Electrons
Boosting superconductivity by metallic reservoirs is the essence of Kivelson's bilayer proposal. One layer provides pairing to the electrons, while the weakly coupled metal provides additional phase coherence to those pairs by mediating extended-range pair-pair coupling. Demonstrating significant and unambiguous performance gains with strong-coupling methods for such set-ups had been difficult. In the present work, we study these systems doped away from half-filling, corresponding to a partially spin-polarized 1D Anderson- or Kondo-lattice. We show that this breaks the coexistence of dominant superconducting and density-density correlations decisively in favour or the former. Consequently, we provide evidence that in this doped regime, superconducting near-long-range order is not precluded by a small charge-gap in the thermodynamic limit, as we have recently shown to be the case at half-filling [JE Ebot $et$ $al.$, arXiv:2602.11153 [cond-mat.supr-con]]. We study the complex manner in which the enhancement of superconductivity in the pairing layer depends on the parameters of the metal, and especially that both pairing-limited and stiffness-limited regimes may appear in these systems. In addition to superconducting bilayers, our results are relevant, via a particle-hole transformation, for heavy-fermion Kondo-lattice materials in magnetic fields, as we provide previously lacking insight on the competition between antiferromagnetic and easy-plane magnetism, as well as a route for comprehensive indirect tests of Kivelson's bilayer proposal well beyond previous capabilities.
title Enhancement of superconducting stiffness in hybrid superconducting-metallic bilayers
topic Superconductivity
Quantum Gases
Strongly Correlated Electrons
url https://arxiv.org/abs/2604.28187