Superconductivity due to co-operative Kondo effect in Pu 115's

TL;DR

This paper proposes a theory explaining the anomalous superconducting properties of PuCoGa$_5$ and PuRhGa$_5$ through a two-channel Kondo effect, highlighting a novel pairing mechanism driven by valence fluctuations.

Contribution

It introduces a new theoretical framework based on two-channel interference and symplectic large-N approach to explain superconductivity in Pu 115 compounds.

Findings

Maximum critical temperature occurs near degenerate valence levels.

Superconducting order parameter symmetry depends on conduction channel interference.

The theory successfully accounts for anomalous properties of PuCoGa$_5$ and PuRhGa$_5$.

Abstract

We outline key elements of a theory that accounts for anomalous properties of the PuCoGa$_5$ and PuRhGa$_5$ compounds as a consequence of a two-body interference between two Kondo screening channels. Virtual valence fluctuations of the magnetic Pu configurations create two conduction channels of different symmetry. Using the symplectic large-N approach, we are able to demonstrate our pairing mechanism in an exactly solvable large-N limit. The critical temperature reaches its maximum when the energy levels of excited valence configurations are almost degenerate. The symmetry of the order parameter is determined by the product of the Wannier form factors in the interfering conduction channels.