Electronic inhomogeneity in a Kondo lattice

TL;DR

This paper reveals that nonmagnetic impurities cause local suppression of superconductivity in a Kondo lattice system, leading to electronic inhomogeneity similar to a 'Swiss cheese' pattern, with implications for understanding correlated electron materials.

Contribution

It demonstrates the presence of electronic inhomogeneity caused by impurities in a Kondo lattice, expanding the understanding of inhomogeneity in strongly correlated f-electron systems.

Findings

Nonmagnetic impurities suppress superconductivity locally.

Impurities create inhomogeneous electronic states resembling 'Swiss cheese'.

The phenomenon can be generalized to other Kondo lattice materials.

Abstract

Inhomogeneous electronic states resulting from entangled spin, charge, and lattice degrees of freedom are hallmarks of strongly correlated electron materials; such behavior has been observed in many classes of d-electron materials, including the high-Tc copper-oxide superconductors, manganites, and most recently the iron-pnictide superconductors. The complexity generated by competing phases in these materials constitutes a considerable theoretical challenge-one that still defies a complete description. Here, we report a new manifestation of electronic inhomogeneity in a strongly correlated f-electron system, using CeCoIn5 as an example. A thermodynamic analysis of its superconductivity, combined with nuclear quadrupole resonance measurements, shows that nonmagnetic impurities (Y, La, Yb, Th, Hg and Sn) locally suppress unconventional superconductivity, generating an inhomogeneous electronic "Swiss cheese" due to disrupted periodicity of the Kondo lattice. Our analysis may be generalized to include related systems, suggesting that electronic inhomogeneity should be considered broadly in Kondo lattice materials.