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TT: Fachverband Tiefe Temperaturen

TT 11: Heavy Fermions

TT 11.3: Talk

Monday, March 18, 2024, 15:30–15:45, H 3005

Origin of the non-Fermi-liquid behavior in CeRh₂As₂ — •Pavlo Khanenko^{1, 2}, Konstantin Semeniuk¹, Daniel Hafner¹, Jacintha Banda¹, Thomas Lühmann¹, Javier F. Landaeta¹, Florian Bärtl³, Tommy Kotte³, Joachim Wosnitza^2,3, Gertrud Zwicknagl⁴, Christoph Geibel¹, Seunghyun Khim¹, Elena Hassinger², and Manuel Brando¹ — ¹Max Planck Institute for Chemical Physics of Solids, Germany — ²Institut für Festkörper- und Materialphysik, TU Dresden, Germany — ³Hochfeld-Magnetlabor Dresden (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence, Germany — ⁴Institute for Mathematical Physics, Technische Universität Braunschweig, Germany

Unconventional superconductivity appears near magnetic quantum critical points (QCPs). This seems to be the case also for CeRh₂As₂ which is a multi-phase heavy-fermion superconductor (T_c = 0.31 K). Furthermore, another ordered state is observed below T₀ ≈ 0.48 K whose nature is unclear, possibly a quadrupolar order. In addition, NQR/NMR experiments have detected an antiferromagnetic order below T_c. The presence of a QCP is indicated by the non-Fermi-liquid (NFL) behavior observed above the ordered states in both the specific heat, C(T)/T ∝ T^−0.6, and the resistivity, ρ(T) ∝ √T. Here, we present specific-heat measurements taken at a field applied at various angles α with respect to the crystallographic c axis. We observe that the NFL behavior depends very weakly on the field and on the angle α, a result that is at odds with that observed in standard magnetic QCPs. Possible origins for this unusual NFL behavior are discussed.

Keywords: Kondo effect; non-Fermi-liquid; unconventional superconductivity