Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 47: New Materials: mainly thermoelectric and nanomechanical Properties

HL 47.3: Talk

Wednesday, March 24, 2010, 16:30–16:45, H14

Thermoelectric properties and electronic structure of NiTSn(T = Ti, Zr, Hf) Heusler compounds. — •S. Ouardi¹, G. H. Fecher¹, B. Balke¹, G. Stryganyuk¹, C. Felser¹, and E. Ikenaga² — ¹Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, Mainz, Germany — ²Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo, Japan

Heusler compounds with 1:1:1 composition attracted attention as potential candidates for thermoelectric applications. Complex C1_b compounds such as NiTiSn are promising n-type thermoelectrical materials. In the present study we have used stoichiometric doping of such compounds to investigate its influence on the transport properties. Our work focuses on a systematic investigation of pure NiTSn systems and the substituted derivates NiT_1−xT′_xSn (T, T′= Ti, Zr, and Hf). The C1_b structure was verified for all compounds by powder X-ray diffraction. The effect of electron- or hole- doping was studies by electrical conductivity, Seebeck coefficient, and thermal conductivity measurement in the temperature range from 2 K to 300 K using a physical properties measurement system (PPMS). The electronic structure - in particular of the valence band - was studied by photoelectron spectroscopy excited by hard X-ray synchrotron radiation at BL-47XU of SPring-8 (Japan). All experimental findings are well supported by first principle calculations of the electronic structure.

This work was financially supported by the Stiftung für Inovation Rheinland Pfalz.