Colossal Seebeck coefficient in strongly correlated semiconductor FeSb2A. Bentien1, S. Johnsen2, G. K. H. Madsen2, B. B. Iversen2 and F. Steglich1
1 Max Planck Institute for Chemical Physics of Solids - Nöthnitzer Straße 40, 01187 Dresden, Germany
2 Department of Chemistry, University of Aarhus - Langelandsgade 140, 8000 Århus C, Denmark
received 15 August 2007; accepted in final form 16 August 2007; published October 2007
published online 17 September 2007
For more than a decade strongly correlated semiconductors and Kondo insulators have been considered as potential thermoelectric materials. Such materials have large d- or f-character of the electronic band structure close to the Fermi level that theoretically leads to Seebeck coefficients (S) with large magnitudes. In this work it is shown for the first time that the strongly correlated semiconductor FeSb2 exhibits a colossal Seebeck coefficient of ~ -45000 VK-1 at 10 K. The thermoelectric power factor , where is the electrical resistivity, reaches a record high value of ~ 2300 WK-2 cm-1 at 12 K and is 65 times larger than that of the state-of-the-art Bi2Te3-based thermoelectric materials. However, due to a large lattice thermal conductivity the dimensionless thermoelectric figure of merit is only 0.005 at 12 K. Nonetheless, the potential of FeSb2 as a future solid-state thermoelectric cooling device at cryogenic temperatures is underlined.
72.20.-i - Conductivity phenomena in semiconductors and insulators.
75.50.Pp - Magnetic semiconductors.
71.28.+d - Narrow-band systems; intermediate-valence solids.
© Europhysics Letters Association 2007