Skutterudite Results Shed Light on Heavy Fermion Physics

TL;DR

This paper reviews selected heavy fermion skutterudite compounds, focusing on PrFe4P12 and URu2Si2, highlighting progress in understanding their order parameters and phase diagrams, and discussing theoretical challenges like Kondo coupling and exciton modes.

Contribution

It provides a comparative analysis of PrFe4P12 and URu2Si2, offering new insights into their order parameters and phase behavior, and discusses theoretical issues in heavy fermion physics.

Findings

Identification of a non-magnetic multipolar order in PrFe4P12

Similarities in phase diagrams of PrFe4P12 and URu2Si2

Discussion of Kondo coupling and exciton modes in low charge carrier systems

Abstract

Only few selected examples among the great diversity of anomalous rare earth skutterudite are reviewed. Focus is first given on PrFe4P12 in comparison with URu2Si2. For PrFe4P12, great progress has been made on determining the nature of the order parameter (OP). A non magnetic order parameter with a multipolar component emerges here while for URu2Si2 the nature of the so-called hidden order remains mysterious. The two systems have several similarities in their temperature--pressure (T, P) and magnetic field--temperature (H, T) phase diagrams, in their spin dynamics, in their nesting character and in their high sensitivity to impurities. Advances on one side must stimulate new views on the other. Besides general considerations on the choice of the OP, a simple basic problem is the treatment of the Kondo coupling in a system with low charge carrier number for the cases of uncompensated and compensated semi-metal. An interesting problem is also the possible decoupling between exciton modes and itinerant carriers.