Superconductivity and spin fluctuations in {Th,U}Pt4Ge12 skutterudites

Merging experimental data and ab initio calculations, we report on ThPt4Ge12 and UPt4Ge12 as further members of germanium-based skutterudites. For ThPt4Ge12 electron-phonon coupled superconductivity develops below T-c=4.75 K, ascribed to intrinsic features of the Pt-Ge framework where Ge-p states dominate the electronic structure at the Fermi energy. Ruderman-Kittel-Kasuya-Yosida coupling via the Ge framework is too weak to enable magnetic ordering in nonsuperconducting UPt4Ge12.