- 07 Nov 2022
- 14h00 - 18h00
Konstantin Semeniuk I Superconductivity and quadrupole density wave in CeRh2As2
Konstantin Semeniuk, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
The Kondo lattice compound CeRh2As2 is an unconventional superconductor (Tc ≈ 0.3 K) exhibiting a first order transition between two distinct superconducting states when magnetic field is applied along the c axis of the tetragonal unit cell . The high-field state is characterised by the odd-parity pairing and a purely orbital-limited upper critical field of at least 15 T . One of the key ingredients for realising such a phase diagram is a strong Rashba spin-orbit coupling caused by the lack of local inversion symmetry at the Ce sites. Besides the superconductivity, CeRh2As2 also displays a phase transition at ~0.4 K, proposed to be a quadrupole-density-wave (QDW) instability .
In our latest experiments we investigated the interplay between the QDW state and superconductivity. Heat capacity and resistivity measurements on new higher-quality single crystals of CeRh2As2 clearly indicate that the QDW is not involved in the superconducting phase switching. This result is further reinforced by our high-pressure resistivity study, which at the same time strongly suggests the influence of the QDW order on the ab-plane upper critical field. We discuss potential scenarios of the interaction between the two states and consider their relevance in the context of quantum critical behaviour.
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