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TT: Fachverband Tiefe Temperaturen
TT 34: Fe-based Superconductors
TT 34.1: Talk
Wednesday, March 29, 2023, 11:30–11:45, HSZ 103
Efficient tuning of the superconductor BaNi2As2 by Calcium substitution - Single crystal Growth and Characterization — •Fabian Henßler, Kristin Willa, Mehdi Frachet, Tom Lacmann, Christoph Meingast, Michael Merz, Amir-Abbas Haghighirad, and Matthieu Le Tacon — Institut für Quantenmaterialien und Technologien, KIT Karlsruhe, Deutschland
BaNi2As2 is a highly tunable superconductor, which is non-magnetic and isostructural to the Fe-based parent compound BaFe2As2. Beyond superconductivity, recent publications reinforce the strong interplay between nematicity, charge density waves (CDW), and structural distortions [1,2,3]. At about 145 K, an incommensurate CDW forms, which coincides with a small lattice distortion (δ∼10−4) [4]. At slightly lower temperatures (TS), the system undergoes a first-order transition, which can be suppressed e.g. by P- or Sr-substitution. Thereby, the superconducting transition temperature Tc can be enhanced by a factor of six [5]. In the case of Sr substitutions, however, a concentration as large as xSr ∼ 0.7 is required. As an alternative, we report on the growth of Ca-substituted single crystals with Ca content up to xCa ∼ 0.1. Specific heat and electrical transport measurements indicate that Ca is about eight times more efficient than Sr to suppress TS.
[1] M. Frachet et al., arXiv:2207.02462 (2022)
[2] C. Meingast et al., Phys. Rev. B 106, 144507 (2022)
[3] S. M. Souliou et al., arXiv:2207.07191 (2022)
[4] M. Merz et al., Phys. Rev. B 104, 184509 (2021)
[5] C. Eckberg et al., Nat. Phys. 16, 346-350 (2020)