SKM 2021 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 5: Poster Session KFM

KFM 5.24: Poster

Dienstag, 28. September 2021, 16:00–17:00, P

Intrinsic electronic structure of TiCoSb half-heusler single crystals by ARPES — •Federico Serrano-Sanchez¹, Mengyu Yao¹, Suchitra Prasad¹, Andrei Gloskovskii², Alexander Fedorov³, Gudrun Auffermann¹, Ulrich Burkhardt¹, Gerhard Fecher¹, Claudia Felser¹, Yu Pan¹, and Chenguang Fu¹ — ¹MPI-CPfS, Dresden, Germany — ²DESY, Hamburg, Germany — ³HZB fur Materialien und Energie, Berlin, Germany

In half-Heulser thermoelectric TiCoSb, defects yield elusive intrinsic properties and a wide range of properties reported in the literature[1-3]. To tackle these inconsistencies, single crystals of TiCoSb have been grown and their crystallographic and electronic properties characterized. The crystals display an almost perfect stoichiometry, while XRD display the half-Heusler F43m structure only. Electrical resistivity shows a metallic behaviour due to the intrinsic p-type nature of the crystals, while the temperature evolution of the conductivity indicates the presence of point defects. Nevertheless, no in-gaps states in the valence band top are detected by HAXPES, suggesting the absence of interstitial defects. ARPES displays a diffusive surface state above the VBM and the band convergence at the L and Γ band maxima points, which is compared to previous theoretical calculations and gives a further hint on the excellent electronic performance of this family of materials.

[1] S. Ouardi et al., Phys. Rev. B - Condens. Matter Mater. Phys., 2012, 86, 045116. [2] E. Rausch et al., Acta Mater., 2016, 115, 308-313. [3] P. Dey and B. Dutta, Phys. Rev. Mater., 2021, 5, 35407.