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TT: Fachverband Tiefe Temperaturen

TT 52: Superconductivity: Fe-based Superconductors – FeSe and others

TT 52.11: Vortrag

Mittwoch, 18. März 2015, 12:15–12:30, H 2053

Superconductivity in 112 type bismuthides and antimonides — Reiner Retzlaff, Alexander Buckow, Jose Kurian, •Soumya Ray, and Lambert Alff — Institute of Materials Science, Technische Universität Darmstadt, Germany

We report the epitaxial growth of As free and phase pure thin films of the 112-pnictide compounds LaPd_xPn₂ (Pn = Sb, Bi) grown onto (100) MgO substrates by molecular beam epitaxy [1,2]. X-ray diffraction, reflection high-energy electron diffraction, and X-ray photoelectron spectroscopy confirm the HfCuSi₂ structure of the material with a peculiar pnictogen square net layer. The superconducting transition temperature, T_c, varies little with Pd concentration. LaPd_xSb₂ has a higher T_c (3.2 K) by about 20% as compared to LaPd_xBi₂ (2.7 K). Fe substitution of Pd leads to a rapid decay of superconductivity. Our results suggest that these superconductors are conventional type II, and that superconductivity occurs in the metal-pnictogen layer as in all iron-pnictide superconductors rather than in the pnictogen square net layer.

[1] A. Buckow, K. Kupka, R. Retzlaff, J. Kurian, and L. Alff, Appl. Phys. Lett. 101, 162602 (2012).

[2] A. Buckow, R. Retzlaff, J. Kurian, and L. Alff, Supercond. Sci. Technol. 26, 015014 (2013).