Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity: Poster Session
TT 30.5: Poster
Donnerstag, 8. September 2022, 15:00–18:00, P1
In search of the superconducting symmetries of CeRh2As2 — •Fabian Jakubczyk1,2, Julia M. Link1,2, and Carsten Timm1,2 — 1Institute of Theoretical Physics, Technische Universität Dresden, 01062 Dresden, Germany — 2Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
Multiphase unconventional superconductivity is a rare phenomenon, which has recently been discovered in the tetragonal but locally noncentrosymmetric heavy-fermion compound CeRh2As2. Here, the transition between two distinct superconducting phases occurs as a function of magnetic field applied along the c axis. At µ0H* ≈ 4 T the superconductor changes from a low-field to a high-field state with a large critical field of µ0 Hc2 = 14 T. However, for in-plane fields only the low-field phase appears, with µ0 Hc2 = 2 T. Furthermore, at T0 ≈ 0.4 K a transition to a suggested quadrupole-density-wave state was reported, whilst the low-field superconducting state is reached at TSCI = 0.26 K. An in-plane magnetic field of about 9 T transforms this density-wave state into another nonmagnetic phase with quadrupolar degrees of freedom through a first-order transition. Recent As-NQR experiments further increased the variety of intriguing phenomena in this material, for they detected the onset of antiferromagnetism within the superconducting low-field phase, i.e. at TN<TSCI. In order to study the coexistence and interplay of the potential superconducting, magnetic and density wave phases, as well as the effect of an external magnetic field, we conduct a symmetry analysis followed by the construction of a Landau-type energy functional. Thereby we can give a statement about the probable symmetries of the superconducting phases.