Competing d-Wave and p-Wave Spin-Singlet Superconductivities in the Two-Dimensional Kondo Lattice

TL;DR

This paper investigates how different superconducting pairings emerge in the two-dimensional Kondo lattice, revealing a transition from d-wave to p-wave symmetry as interaction strength increases, driven by Fermi surface changes.

Contribution

It demonstrates the emergence and competition of d-wave and p-wave spin-singlet superconductivities in the Kondo lattice using the dual-fermion approach.

Findings

d-wave pairing dominates at weak coupling

p-wave pairing becomes favorable at strong coupling

superconducting symmetry crossover linked to Fermi surface evolution

Abstract

The Kondo lattice model describes a quantum phase transition between the antiferromagnetic state and heavy-fermion states. Applying the dual-fermion approach, we explore possible superconductivities emerging due to the critical antiferromagnetic fluctuations. The d-wave pairing is found to be the leading instability only in the weak-coupling regime. As the coupling is increased, we observe a change of the pairing symmetry into a p-wave spin-singlet pairing. The competing superconductivities are ascribed to crossover between small and large Fermi surfaces, which occurs with formation of heavy quasiparticles.