Stabilization of the collective Kondo semiconducting state by Sb doping in CeNiSn$_{1-x}$Sb$_{x}$ and the criterion of its appearance

TL;DR

This paper demonstrates that Sb doping in CeNiSn induces a stable Kondo semiconducting state primarily through electron addition, with atomic disorder playing a minimal role, and clarifies the criteria distinguishing Kondo semiconductors from other insulators.

Contribution

It reveals that Sb doping stabilizes the Kondo semiconducting state in CeNiSn mainly via electron doping, providing a clear criterion for its formation distinct from disorder effects.

Findings

Sb doping induces a full-gap in CeNiSn.

Extra electrons from Sb contribute to Kondo singlet formation.

Atomic disorder has minimal impact on gap formation.

Abstract

Semimetallic CeNiSn is shown to transform into a Kondo semiconductor upon the substitution of few percent of Sb for Sn. The full-gap formation is not decisively influenced by the atomic disorder introduced by the substitution. Instead, the extra valence electrons introduced with the Sb doping (one per Sb atom) contribute to the formation of the collective Kondo spin-singlet state at low temperatures, as seen by a reduction of magnetic susceptibility. The definition of the Kondo semiconductor is provided and the difference with either the band-Kondo or the Mott-Hubbard insulators is stressed.