Flux Growth, Crystal Structures, and Electronic Properties of the Ternary Intermetallic Compounds Ca3Pd4Bi8 and Ca3Pt4Bi8

Abstract

Reaction of the elements yielded Ca3Pt4Bi8 and CaPtBi, which are, to the best of our knowledge, the first reported ternary Ca–Pt–Bi compounds. The compounds crystallize isostructural to the Pd analogs Ca3Pd4Bi8 (own structure type) and CaPdBi (TiNiSi structure type), respectively. Employing a multistep temperature treatment allows for the growth of mm-sized single crystals of Ca3Pd4Bi8 and Ca3Pt4Bi8 from a Bi self-flux. Their crystal structures can be visualized as consisting of a three-dimensional extended polyanion [M4Bi8]6– (M = Pd, Pt), composed of interlinked M–Bi chains propagating along the c direction, and Ca2+ cations residing in one-dimensional channels between the chains. First-principles calculations reveal quasi-one-dimensional electronic behavior with reduced effective electron masses along [001]. Bader analysis points to a strong anionic character of the M species (M = Pd, Pt) in Ca3M4Bi8. Thus, it is more appropriate to address the compounds Ca3Pd4Bi8 and Ca3Pt4Bi8 as a palladide and platinide, respectively. Magnetization measurements indicate diamagnetic behavior with no indications for superconductivity down to 2 K. Electrical resistivity data are consistent with metallic behavior and suggest predominant electron–phonon scattering.