Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 43: Correlated Electrons: Heavy Fermions 2

TT 43.10: Talk

Thursday, March 26, 2009, 18:15–18:30, HSZ 301

Narrow gap and electron correlation effects in FeSb₂ — •Peijie Sun¹, Niels Oeschler¹, Simon Johnsen², Bo B. Iversen², and Frank Steglich¹ — ¹Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — ²Department of Chemistry, University of Aarhus, Denmark

Heavy-fermion, or alternatively correlated, semiconductors are of both fundamental and practical interest due to their narrow energy gap and correlated bands at the gap edges. This talk will focus on FeSb₂, a new d-based correlated semiconductor showing thermodynamics and band structure similar to FeSi. Correlated electrons in FeSb₂ manifest themselves in many physical properties like specific heat, magnetic susceptibility, and optical spectra. In particular, we will show a huge thermoelectric response in FeSb₂ below 50 K [1] which is also attributed to the correlated gap. Different to FeSi, a second energy gap (<100 K) was confirmed to be intrinsic to FeSb₂ by electrical, thermal transports and specific heat measurements. This largely contributes to the extraordinarily enhanced thermoelectricity at the same temperature range. Comparison of FeSb₂ to its Ru and As substituted homologues will be also presented.

[1] A. Bentien et al, Europhys. Lett. 80 (2007) 17008.