Thermodynamic Properties of the Non-centrosymmetric Type-I Superconductor Rh₂Ga₉ and Ir₂Ga₉

Abstract

We report low-temperature specific heat measurements on the single-crystalline non-centrosymmetric superconductors T 2 Ga 9 (T = Rh, Ir) with T c = 1.95 and 2.25 K. Electronic contribution on the specific heat, C el , in each compound is well described by the BCS scheme, suggesting that both Rh 2 Ga 9 and Ir 2 Ga 9 fully open an isotropic gap in the superconducting state. The values of Δ C /γ T c and 2Δ(0)/ k B T c indicate that both compounds are categorized as a weak coupling superconductor. The value of κ obtained from specific heat as a function of magnetic field strongly suggestes that T 2 Ga 9 is a type-I superconductor.