Unconventional Superconductivity from Local Spin Fluctuations in the Kondo Lattice

TL;DR

This paper demonstrates that local spin fluctuations in the Kondo lattice can induce robust s-wave superconductivity, challenging the conventional view that non-local fluctuations are necessary for heavy-fermion superconductivity.

Contribution

It reveals a novel mechanism for heavy-fermion superconductivity driven by local spin fluctuations, using dynamical mean-field theory on the Kondo lattice model.

Findings

Robust s-wave superconductivity observed in the heavy-fermion state.

Superconductivity linked to heavy quasiparticle band formation.

Local spin fluctuations can induce unconventional pairing mechanisms.

Abstract

The explanation of heavy-fermion superconductivity is a long-standing challenge to theory. It is commonly thought to be connected to non-local fluctuations of either spin or charge degrees of freedom and therefore of unconventional type. Here we present results for the Kondo-lattice model, a paradigmatic model to describe heavy-fermion compounds, obtained from dynamical mean-field theory which captures local correlation effects only. Unexpectedly, we find robust s-wave superconductivity in the heavy-fermion state. We argue that this novel type of pairing is tightly connected to the formation of heavy quasiparticle bands and the presence of strong local spin fluctuations.