Abstract
Formation, crystal chemistry, and physical properties were investigated for the solid-solution ( is a vacancy) deriving from binary clathrate with a solubility limit of Pt atoms/f.u. at . Structural investigations throughout the homogeneity region confirm isotypism with the cubic primitive clathrate type-I structure (space group type ) and lattice parameters ranging from for to for . Phase relations for the region concerning the clathrate solution were derived at subsolidus temperatures as well as at . Transport properties evidence electrons as the majority charge carriers in the system with a slight dependency on the Pt content. The system is located close to a semiconducting regime with a gap in the electronic density of states of a few thousand K. No low temperature maximum is obvious from thermal conductivity which is dominated by the lattice contribution. Thermal conductivity furthermore documents a high efficiency of phonon scattering on vacancies.
1 More- Received 18 July 2007
DOI:https://doi.org/10.1103/PhysRevB.76.195124
©2007 American Physical Society