SKM 2021 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Unconventional Superconductors

TT 19.3: Vortrag

Donnerstag, 30. September 2021, 11:45–12:00, H6

Angular dependence of the superconductivity in CeRh₂As₂ — •Javier Landaeta¹, Pavlo Khanenko¹, Jacinta Banda¹, Ilya Sheikin², Sanu Mishra², Seunghyun Khim¹, Manuel Brando¹, Christoph Geibel¹, and Elena Hassinger¹ — ¹Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany — ²Univ. Grenoble Alpes, CNRS, LNCMI EMFL, F-38042 Grenoble, France

CeRh₂As₂ is an unconventional superconductor with multiple superconducting phases. When µ₀H∥ c, this material shows a field-induced transition from a low-field superconducting state SC1 to a high-field SC2 with critical field H_c2 = 14 T and T_c = 0.26 K. For µ₀H∥ ab, only the SC1 with H_c2 = 2 T is observed. The phase-diagrams and their anisotropy might be explained by the influence of Rashba-spin-orbit coupling at the Ce sites where the inversion symmetry is broken locally. Above T_c, a possibly quadrupolar phase is present at T₀ ≈ 0.4 K, whose influence on the superconducting state remains unknown. Here, we present a comprehensive study of the angular dependence of the upper critical fields and T₀ using low temperature magnetic ac susceptibility, specific heat and torque in single crystalline CeRh₂As₂. The SC2 state is strongly suppressed when rotating the magnetic field away from the c-axis and disappears for an angle of 35^∘. We find that the H_c2 of SC2 for angles departing from the c axis is attained when the in-plane component of the field reaches the in-plane Pauli limit. This result corroborates idea that the field-induced state SC2 is an odd-parity state with a d-vector in the plane in CeRh₂As₂.