FeSb2

FeSb2 is an iron antimonide, an intermetallic compound with the chemical formula FeSb2. It crystallizes in an orthorhombic marcasite-type structure and is studied as a narrow-gap semiconductor. The energy gap is small, typically described as tens to a few hundred meV, and can vary with sample quality and measurement technique. The electronic structure shows signs of strong electron correlations, which can give rise to transport behavior reminiscent of Kondo insulators in some regimes.

In terms of transport properties, FeSb2 exhibits an exceptionally large Seebeck coefficient at cryogenic temperatures, with reported values reaching several tens of millivolts per kelvin near 10 K. This colossal thermopower, together with its moderate electrical conductivity, has made FeSb2 a focus of thermoelectric research aimed at low-temperature applications. The material generally shows semiconducting temperature dependence, and its thermal conductivity is relatively moderate for a narrow-gap semiconductor. Researchers explore approaches such as doping and nanostructuring to optimize thermoelectric performance.

Preparation and forms of FeSb2 are typically achieved by solid-state reactions or crystal growth from high-temperature routes, often under inert or reducing atmospheres to stabilize the marcasite phase. It can be obtained as polycrystalline material or as single crystals for fundamental studies and thermoelectric measurements.

Applications and context: FeSb2 is primarily of scientific interest as a model system for correlated electron phenomena and for potential cryogenic thermoelectric applications. Safety considerations include the toxicity of antimony compounds, requiring standard laboratory precautions.