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Triplet pairing via Kondo hybridization - applications to UTe$_2$ and CeRh$_2$As$_2$

ORAL

Abstract

We explore pairing mechanisms for triplet superconductivity mediated by Kondo interactions, relevant for UTe$_2$ and CeRh$_2$As$_2$. In these systems, the upper critical field violates the Pauli limit by an order of magnitude, and there are multiple distinct superconducting phases which appear to be enhanced and even enabled by strong magnetic fields. Taken together, the experimental puzzles raised by these systems challenge our current understanding of heavy fermion superconductivity and raise the intriguing possibility of a very new kind of superconductivity driven by the local moments of U and Ce. We seek to unify the Kondo physics with the triplet pairing in a coherent framework. With this motivation, we present a mean-field analysis of a simple two-channel Kondo model which has two spins at locally-noncentrosymmetric sites in the unit cell, inspired by UTe$_2$ and CeRh$_2$As$_2$, which illustrates the emergence of local triplet correlations as a result of Kondo hybridization with spin-orbit coupled local moments. In the spirit of a resonating valence bond picture, the superconductivity can be understood as the condensation of spin-triplet pre-formed pairs which are odd under exchange of the two U/Ce sites.

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Authors

  • Tamaghna Hazra

    Rutgers University

  • Blakesley Burkhart

    Massachusetts Institute of Technology, None, University of Colorado Boulder, Virginia Tech, MIT Haystack Observatory, University of Alabama, Johns Hopkins University, University of Maryland College Park, University of Illinois Urbana Champaign, Rutgers University, Institute of Solar-Terrestrial Physics, New Jersey Inst of Tech, Flatiron Institute, Rutgers, The State University of New Jersey, University of KwaZulu-Natal, Los Alamos National Laboratory, The College of William \& Mary, Cornell University, Cornell University, California Institute of Technology, California Institute of Technology, Max Planck Institute for Gravitational Physics (Albert Einstein Institute), New Jersey Institute of Technology, New Jersey Institute of Tech, University of Applied Sciences and Arts Northwestern Switzerland, Princeton University, University of Pittsburgh, DEVCOM Army Research Lab, University of Louisville, University of Cape Town, Rutgers University/Flatiron Institute, Center for Astrophysics, Harvard & Smithsonian, Research School of Astronomy and Astrophysics, The Australian National University, Rutgers, the State University of New Jersey