Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Correlated Electrons: Poster Session

TT 21.8: Poster

Mittwoch, 7. September 2022, 15:00–18:00, P1

Growth and characterization of KFe_1−xAg_1+yCh₂ — •Jutta Püttmann, N. S. Sangeetha, Andreas Kreyßig, and Anna E. Böhmer — Experimentalphysik IV, Universitätstraße 150, 44801 Bochum

Iron-based 122-compounds with ThCr₂Si₂ structure have been intensely studied over the past decades. K-based chalcogenides, such as K_xFe_2−δSe₂ have attracted attention due to their high-temperature superconductivity, their strong electronic correlations, and their complex microstructure dominated by vacancies and phase separation. Recently, KFe_0.8Ag_1.2Te₂ has been found to provide the possibility to study an iron chalcogenide 122-systems without vacancies on the alkali site and to investigate a superstructure in the Fe/Ag plane with an interesting magnetic and nematic ordering [1, 2].

The growth of K-based single crystals is challenging due to the high vapor pressure and reactivity of potassium. We developed a new, affordable and efficient growth technique using containers made from high-temperature resistant stainless steel that can be sealed without any air-exposure of the starting materials. The growth of KFe_1−xAg_1+yCh₂-crystals by self-flux was optimized with respect to the starting material composition. The obtained crystals were characterized by EDX and XRD. The XRD patterns were analyzed for signs of superstructure in the Fe/Ag plane. Additionally, low-temperature measurements were carried out to confirm the magnetic transitions.

[1] Yu Song et al., Phys. Rev. Lett. 122, 087201 (2019)

[2] Yu Song et al. Phys. Rev. Lett. 123, 247205 (2019)