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arXiv · 2411.07201

Fractionalized Superconductivity Mediated by Majorana Fermions in the Kitaev-Kondo Lattice

Matthew Bunney·Urban F. P. Seifert·Stephan Rachel·Matthias Vojta
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Abstract

Superconductivity usually emerges from a metallic normal state which follows the Fermi-liquid paradigm. If, in contrast, the normal state is a fractionalized non-Fermi liquid, then pairing may either eliminate fractionalization via a Higgs-type mechanism leading to a conventional superconducting state, or pairing can occur in the presence of fractionalization. Here we discuss a simple model for the latter case: Using a combination of perturbation theory and functional renormalization group, we show that the Kitaev--Kondo lattice model displays a fractionalized superconducting phase at weak Kondo coupling. This phase is characterized by Cooper pairing of conventional electronic quasiparticles, coexisting with a spin-liquid background and topological order. Depending on the sign of the Kitaev coupling, we find the pairing to be either of chiral $d$-wave or $p$-wave type for extended doping regions around the van-Hove filling. We discuss applications and extensions.

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Matthew Bunney, Urban F. P. Seifert, Stephan Rachel, Matthias Vojta. 2024-11-11. Fractionalized Superconductivity Mediated by Majorana Fermions in the Kitaev-Kondo Lattice. https://doi.org/10.1103/physrevlett.134.206602

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