Strongly Correlated Intermetallics: $$\mathbf FeSb _\mathbf{2}$$ F eSb 2

\({\mathrm{FeSb }}_{2}\) exhibits extraordinary physical properties with a colossal thermopower reaching 45 mV/K at \(\sim \)10 K, while maintaining fairly low electrical resistivity. This results in extremely high thermoelectric power factors exceeding 2,000 \(\upmu {\mathrm{W }}/({\mathrm{K }}^{2} \cdot \,{\mathrm{cm }})\). If the thermal conductivity can be reduced to a few W/(K\(\cdot \)m), then a thermoelectric figure of merit of unity is within reach at cryogenic temperatures opening up for a new solid state cooling technology. Furthermore, the physical properties of \(\mathrm{FeSb }_{2}\) are also of immense fundamental interest since the material is believed to be a strongly correlated narrow band gap semiconductor. In the last decade a wide range of studies have explored the synthesis, structure and properties of \(\mathrm{FeSb }_{2}\) and related materials, and here an overview of the efforts is provided.