SmB6: A material with anomalous energy distribution function of charge carriers?

TL;DR

This paper proposes that valence fluctuations in SmB6 cause dynamic impurity energy changes, leading to an unusual energy distribution of charge carriers that differs from conventional semiconductors at zero temperature.

Contribution

It introduces a new perspective on the energy distribution function of localized charge carriers in valence fluctuating semiconductors like SmB6, considering dynamical impurity energy fluctuations.

Findings

Impurity energies fluctuate due to valence changes.

Ground state energy distribution differs from conventional semiconductors.

Provides new interpretation for low-temperature experimental results.

Abstract

We argue that because of valence-fluctuation caused dynamical changes (fluctuations) of impurity energies in an impurity band of valence fluctuating semiconductors both occupied and unoccupied sites can be found in the impurity band above as well as below the Fermi level even in the ground state. As a consequence, the ground state energy distribution function of the subsystem of localized charge carriers for valence fluctuating semiconductors is qualitatively different than one for conventional semiconductors at T = 0 K, what sheds new light on interpretation of experimental results of valence fluctuating semiconductors, e.g. SmB6 and YbB12, at lowest temperatures.