D-wave superconductivity induced by short-range antiferromagnetic correlations in the two-dimensional Kondo lattice model

TL;DR

This paper demonstrates that short-range antiferromagnetic correlations in the two-dimensional Kondo lattice model can induce d-wave superconductivity, with a phase transition between nodal and nodeless states, relevant to heavy fermion superconductors.

Contribution

It introduces a mean field theory showing how local antiferromagnetic correlations induce superconductivity in the Kondo lattice model, revealing a transition between different d-wave states.

Findings

Short-range antiferromagnetic correlations induce superconductivity.

A phase transition exists between nodal and nodeless d-wave states.

Results relate to quasi-two-dimensional heavy fermion superconductors.

Abstract

The possible heavy fermion superconductivity is carefully reexamined in the two-dimensional Kondo lattice model with an antiferromagnetic Heisenberg superexchange between local magnetic moments. In order to establish an effective mean field theory in the limit of the paramagnetic heavy Fermi liquid and near the half-filling case, we find that the spinon singlet pairing from the local antiferromagnetic short-range correlations can reduce the ground state energy substantially. In the presence of the Kondo screening effect, the Cooper pairs between the conduction electrons is induced. Depending on the ratio of the Heisenberg and the Kondo exchange couplings, the resulting superconducting state is characterized by either a d-wave nodal or d-wave nodeless state, and a continuous phase transition exists between these two states. These results are related to some quasi-two dimensional heary fermion superconductors.