Regensburg 2025 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 37: Correlated Electrons: Poster
TT 37.4: Poster
Wednesday, March 19, 2025, 15:00–18:00, P4
Negative Pressure Studies on CeRh2As2 with La Substitution — •Sushma Lakshmi Ravi Sankar1,2, Arushi Yadav1, Manual Brando1, Joachim Wosnitza2, and Seunghyun Khim1 — 1Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany — 2Technische Universität Dresden, 01069 Dresden Germany
CeRh2As2 is a Kondo-lattice system with novel phase diagrams involving a superconducting and an unknown ordered state appearing below Tc and T0, respectively. Recent observations of a suppression of Tc and T0 under external pressure [1] motivated an investigation of a negative pressure study, which can be achieved by a La substitution with Ce. We have succeeded in growing single crystals of (Ce1−xLaxRh2As2) up to x ∼ 0.1. We found a negative pressure effect as the La substitution leads to an increase in the a- and c- lattice parameters (unit cell volume increase by ∼ 0.15% with x = 0.1) while maintaining the CaBe2Ge2-type crystal structure. Resistivity measurements showed that both Tc and T0 decrease with the La substitution to be almost suppressed at x ∼ 0.08, while the resistivity maximum is slightly shifted to a lower temperature. At the same time, the residual resistivity ratio decreases from 2.24 at x = 0 to 1.46 at x = 0.1, indicating additional disorder introduced by the La substitution. This suggests that both the negative pressure effect and the increased disorder should be considered in understanding the evolution of Tc and T0 with the La substitution.
[1] M. Pfeiffer et al., Phys. Rev. Lett. 133, 126506 (2024).
Keywords: Crystal growth; Heavy-fermion system; Kondo effect; Superconducitivity