Low-Temperature Thermal Conductivity of CeRh\(_{2}\)As\(_{2}\)

• Published in: arXiv.org 2022-02
• Main Authors: Onishi, Seita, Stockert, Ulrike, Khim, Seunghyun, Banda, Jacintha, Brando, Manuel, Hassinger, Elena
• Format: Article
• Language: English
• Subjects: Anomalies; Antiferromagnetism; Critical point; Crystal structure; Electrical resistivity; Heat conductivity; Heat transfer; Lorenz number; Low temperature; Magnetic fields; Quadrupoles; Residual resistivity; Single crystals; Superconductivity; Temperature; Thermal conductivity; Unconventional superconductors
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2202.12667

CeRh\(_2\)As\(_2\) is a rare unconventional superconductor (\(T_c=0.26\) K) characterized by two adjacent superconducting phases for a magnetic field \(H \parallel c\)-axis of the tetragonal crystal structure. Antiferromagnetic order, quadrupole-density-wave order (\(T_0 = 0.4\) K) and the proximity of this material to a quantum-critical point have also been reported: The coexistence of these phenomena with superconductivity is currently under discussion. Here, we present thermal conductivity and electrical resistivity measurements on a single crystal of CeRh\(_2\)As\(_2\) between 60 mK and 200 K and in magnetic fields (\(H \parallel c\)) up to 8 T. Our measurements at low \(T\) verify the Wiedemann-Franz law within the error bars. The \(T\) dependence of the thermal conductivity \(\kappa(T)\) shows a pronounced drop below \(T_c\) which is also field dependent and thus interpreted as the signature of superconductivity. However, the large residual resistivity and the lack of sharp anomalies in \(\kappa(T)\) at the expected transition temperatures clearly indicate that samples of much higher purity are required to gain more information about the superconducting gap structure.