Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 29: Unconventional Superconductors
TT 29.5: Talk
Tuesday, March 10, 2026, 10:30–10:45, CHE/0091
Weak competition between magnetism and superconductivity in the heavy-fermion compound CeRh2As2 — •Pavlo Khanenko1,2, Javier F. Landaeta2, Simon Ruet2, Thomas Lühmann2, Konstantin Semeniuk2,3,6, Max Pelly4, Andreas W. Rost4, Grzegorz Chajewski5, Dariusz Kaczorowski5, Christoph Geibel2, Seunghyun Khim2, Elena Hassinger3,6, and Manuel Brando2 — 1Helmholtz Zentrum Dresden Rossendorf, Germany — 2MPI CPfS, Germany — 3TUD, Germany — 4University of St. Andrews, United Kingdom — 5Institute of Low Temperature and Structure Research, Poland — 6KIT Karlsruhe, Germany
The heavy-fermion superconductor CeRh2As2 shows superconductivity at Tc = 0.35 K, which is preceded by another phase (phase I) at T0 = 0.54 K. Recent µSR studies detected an internal magnetic field within phase I and suggested its coexistence with superconductivity. When a magnetic field is applied parallel to the c axis of its tetragonal unit cell, a second superconducting (SC) phase is observed at µ0H* ≈ 4 T. An earlier study has shown that phase I persists up to µ0H0 ≈ 6 T, larger than H*. However, the phase transition disappeared upon entering the SC dome, contradicting thermodynamic considerations. Here, we report magnetic field-dependent ac-susceptibility and magnetostriction measurements on high-quality single crystals. We observed clear evidence of the singularity at H0 in fields up to 7 T and inside the SC dome. Analysis of the phase boundaries in terms of the Ginzburg-Landau theory of coupled order parameters shows a weak competition between phase I and superconductivity.
Keywords: Unconventional superconductors; phase diagrams; thermal expansion; AC susceptibility measurements