Kondo Insulator description of spin state transition in FeSb2

TL;DR

This paper investigates the spin state transition in FeSb2 through thermal and structural measurements, suggesting a Kondo insulator model without structural phase change up to high pressure.

Contribution

It introduces a Kondo insulator perspective for FeSb2 and provides detailed thermal, elastic, and high-pressure structural data.

Findings

Thermal expansion and heat capacity indicate a temperature-induced spin transition.

No structural phase transition observed up to 7 GPa.

Bulk modulus determined as 84 GPa.

Abstract

The thermal expansion and heat capacity of FeSb2 at ambient pressure agrees with a picture of a temperature induced spin state transition within the Fe t_{2g} multiplet. However, high pressure powder diffraction data show no sign of a structural phase transition up to 7GPa. A bulk modulus B=84(3)GPa has been extracted and the temperature dependence of the Gruneisen parameter has been determined. We discuss here the relevance of a Kondo insulator description for this material.