Superconductivity in Re-Based Hexagonal C14 Laves Alloys TRe\(_{2}\) (T = Zr and Hf)

Abstract

The superconductors with Kagome lattice have recently attracted significant interest due to their unconventional superconducting properties. Here, we present a comprehensive investigation of the superconducting properties of the Re-based hexagonal C14 Laves alloys TRe\(_{2}\) (T = Zr and Hf), which contain a hexagonal diamond lattice of T atoms and a breathing Kagome lattice of Re atoms. The electrical resistivity, magnetization, and specific heat measurements confirm type-II bulk superconductivity with T\(_{C}\) = 6.1 K for ZrRe\(_{2}\) and 5.8 K for HfRe\(_{2}\). The superconducting parameters, such as the lower and upper critical field, the coherence length, the penetration depth, the electron–phonon coupling constant, and the density of electronic states at Fermi energy level, are comparable with those of other hexagonal C14 Laves compounds with the same crystal structure. In particular, the values of these parameters are quite close to those of the BCS theoretical framework, suggesting that both ZrRe\(_{2}\) and HfRe\(_{2}\) are weakly coupled type-II superconductors as other hexagonal C14 Laves alloys.