Low temperature specific heat of ternary germanide superconductor La₃Pd₄Ge₄

Low temperature specific heat measurements are performed in a novel ternary superconductor La₃Pd₄Ge₄, which forms U₃Ni₄Si₄-type crystal structure consisting of the combination of alternating units of AlB₂- and BaAl₄ (ThCr₂Si₂)-type layers. The Sommerfeld coefficient γ_n = 27.0 mJ / mol K² and the Debye temperature Θ_D = 256 K are derived from the normal state specific heat. The electron-phonon coupling constant and the electronic density of states at the Fermi level are also derived. Temperature dependence of the superconducting electronic specific heat is well described by the BCS exponential behavior with gap Δ₀ = 0.30 meV. The results suggest La₃Pd₄Ge₄ has fully opened isotropic gap in the superconducting state.