Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Correlated Electrons: Heavy Fermions
TT 6.11: Vortrag
Montag, 25. Februar 2008, 12:15–12:30, EB 202
Enhanced thermopower and related phenomena in the narrow-gap semiconductor FeSb2 — •peijie sun1, niels oeschler1, ulrike köhler1, simon johnsen2, bo brummerstedt iversen2, and frank steglich1 — 1Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 2Department of Chemistry, University of Aarhus, Denmark
A huge Seebeck coefficient of several tens of mV/K around 10 K was found in FeSb2 [1], which shares considerable similarity with the Kondo insulator FeSi with a narrow semiconducting gap. The origin of the enhanced thermopower is yet to be understood. Strong electronic correlation producing enhanced DOS near Fermi level seems to be one possible reason.
We report new results of the Hall effect, specific heat and Nernst effect on high quality single crystals to study the effect of strong correlation. A smaller energy gap of about 50 K was detected in electrical resistivity and Hall coefficient, besides the well known gap at above 300 K. The appearance of the smaller gap accompanies a shoulder in resistivity and a huge peak in Hall coefficient, and thus could be closely related to the enhanced Seebeck coefficient that occurs in the same temperature range.
[1] A. Bentien et al., Europhys. Lett. 80 (2007) 17008.