Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 93: Superconductivity – Poster II
TT 93.1: Poster
Donnerstag, 12. März 2026, 18:00–20:00, P4
The Search for 1144 Phases under Pressure — •Leonard Essich, Kristin Kliemt, and Cornelius Krellner — nstitute of Physics, Goethe University Frankfurt, Germany
Alternative stacking of 122 Fe-based pnictides has enabled the synthesis of the 1144 phase ABFe4As4 (A = alkali, B = alkaline earth). Examples include CaKFe4As4, where a half-collapsed tetragonal phase emerges under pressure, and EuRbFe4As4 or EuCsFe4As4, where Eu magnetism coexists with superconductivity [1,2]. Theoretical studies predict the stability of further 1144 Fe-arsenides and an extension to phosphides (AB(TM)4P4 where TM = Fe, Ru, Co, or Ni). Notably, CaKRu4P4 has been successfully synthesised [1].
This work investigates the synthesis of other 1144 phases under high-pressure conditions, designed to support the incorporation of smaller phosphorus atoms on arsenic lattice positions. Multi-anvil presses offer precise pressure and temperature control, large sample sizes, and adaptable setups for crystal growth research. In this contribution, we present the capabilities of a multi-anvil press, the challenges encountered during sample preparation, and outline the pathway to synthesising 1144 phases. A Walker-type module, previously utilized in our laboratory, contains a 6-8 anvil configuration within a steel cylinder [3]. The choice of pressure-transmitting medium and internal configuration is crucial to achieving the desired outcome in these experiments.
[1] B. Q. Song et al., Phys. Rev. Materials 5, 094802 (2021)
[2] U. S. Kaluarachchi et al., Phys. Rev. B 96, 140501 (2017)
[3] A. A. Haghighirad et al., Cryst. Growth Des. 8, 1961 (2008)
Keywords: 1144 phase; multi-anvil press; Walker-type module; half-collapsed phase; superconductivity