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

We report low temperature specific heat measurements on the single-crystal line non-centrosymmetric superconductors Ta2Ga9 (T = Rh, Ir) with T-e = 1.95 and 2.25 K. Electronic contribution oil the specific heat, C-el in each compound is well described by the BCS scheme, suggesting that both Rh-2 Ga-9 and Ir2Ga9 fully open an isotropic gap in the superconducting state. The values of Delta C/yT(c) and 2 Delta(0)/k(B)T(c) indicate that both compounds tire categorized as a weak coupling superconductor. The value Of K obtained from specific heat as a function of magnetic field strongly suggestes that T2Ga9 is a type-I superconductor.