Univ. Prof.

Dr. Silke BÜHLER-PASCHEN

QUANTUM MATERIALS GROUP

Giant thermopower S of CeNiSn as response to the opening of an energy (pseudo) gap.
4-mirror furnace equipped with halogen lamps for the growth of high-quality single crystals.

STRONGLY CORRELATED ELECTRONIC TOPOLOGY

 

Kondo insulators are strongly correlated electron systems in which the interaction of localized electrons (mostly from unfilled 4f-shells of rare earth elements) with conduction electrons leads to the opening of a narrow energy gap at the Fermi level. The microscopic mechanism for this process is far from being understood. Our recent investigations have focussed on several systems:

 

  • CeRu4Sn6: This tetragonal compound shows strong magnetic anisotropy as well as anisotropic semiconductor-like electrical transport at low temperatures.
  • CeNiSn (image): The opening of the energy gap is accompanied by a huge maximum in the thermoelectric below 10 K. Also the Nernst effect shows very peculiar features.