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TT: Fachverband Tiefe Temperaturen
TT 67: Unconventional Superconductors
TT 67.10: Talk
Thursday, March 21, 2024, 12:15–12:30, H 3007
Exposing quantum criticality and odd-parity superconductivity in CeRh2As2 with hydrostatic pressure — •Konstantin Semeniuk1, Meike Pfeiffer2,1, Javier Landaeta2,1, Seunghyun Khim1, and Elena Hassinger2,1 — 1MPI CPfS, Dresden, Germany — 2TU Dresden, Germany
The locally non-centrosymmetric Kondo-lattice system CeRh2As2 hosts a multi-phase superconductivity (Tc = 0.4 K), a state "Phase I" of currently unknown origin (T0 = 0.5 K), and displays antiferromagnetic ordering below Tc. At the magnetic-field-induced transition between the superconducting (SC) states SC1 and SC2, the parity of the SC order parameter has been proposed to change from even to odd. This idea is supported by the field-temperature phase diagram, but is yet to be verified directly. Alternatively, Phase I or magnetic order could play a role in the phenomenon. Other pertinent questions include the origin of the non-Fermi-liquid behavior, and the impact of the staggered Rashba interaction on the ordered states.
By tuning CeRh2As2 with hydrostatic pressure, we investigated the interplay of Phase I and the SC states. Measurements of resistivity and heat capacity show that Phase I is fully suppressed at P0 = 0.5 GPa, terminating in a quantum critical point (QCP), which is responsible for the non-Fermi-liquid physics and the colossal quasiparticle masses. The SC phase forms an unusually broad dome around the QCP, remaining robust at 2.7 GPa with Tc = 0.2 K. Crucially, the two SC states still exist for P>P0, definitively excluding the involvement of Phase I in the SC1-SC2 switching.
Keywords: Superconductivity; Quantum criticality; Kondo; Heavy fermions; High pressure