CaPtAs: A new noncentrosymmetric superconductor

• Published in: Science China. Physics, mechanics & astronomy Vol. 63; no. 3; p. 237412
• Main Authors: Xie, Wu, Zhang, PeiRan, Shen, Bin, Jiang, WenBing, Pang, GuiMing, Shang, Tian, Cao, Chao, Smidman, Michael, Yuan, HuiQiu
• Format: Journal Article
• Language: English
• Published: Beijing Science China Press 01.03.2020; Springer; Springer Nature B.V
• Subjects: Anisotropy; Astronomy; Classical and Continuum Physics; Critical field (superconductivity); Crystal structure; Density functional theory; Density functionals; Electric properties; Electrical resistivity; Heat; Influence; Magnetic permeability; Observations and Techniques; P waves; Physics; Physics and Astronomy; Single crystals; Specific gravity; Specific heat; Superconductivity; Superconductors; Symmetry; CaPtAs; superconductivity; noncentrosymmetric
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-019-1488-5

We report the discovery of a new noncentrosymmetric superconductor CaPtAs. It crystallizes in a tetragonal structure (space group I 4 1 md , No. 109), featuring three dimensional honeycomb networks of Pt-As and a much elongated c -axis ( a = b = 4.18 Å, and c = 43.70 Å). The superconductivity of CaPtAs with T c = 1.47 K was characterized by means of electrical resistivity, specific heat, and ac magnetic susceptibility. The electronic specific heat C e ( T )/ T shows evidence for a deviation from the behavior of a conventional BCS superconductor, and can be reasonably fitted by a p -wave model. The upper critical field μ 0 H c2 of CaPtAs exhibits a moderate anisotropy, with an in-plane value of around 204 mT and an out-of-plane value of 148 mT. Density functional theory calculations indicate that the Pt-5d and As-4p orbitals mainly contribute to the density of states near the Fermi level, showing that the Pt-As honeycomb networks may significantly influence the superconducting properties.