Huge Thermoelectric Power Factor: FeSb2 versus FeAs2 and RuSb2

The thermoelectric power factor of the narrow-gap semiconductor FeSb2 is greatly enhanced in comparison to the isostructural homologues FeAs2 and RuSb2. Comparative studies of magnetic and thermodynamic properties provide evidence that the narrow and correlated bands as well as the associated enhanced thermoelectricity are only specific to FeSb2. Our results point to the potential of FeSb2 for practical thermoelectric application at cryogenic temperatures and stimulate the search for new correlated semiconductors along the same lines.