Effects of filling in CoSb3: Local structure, band gap, and phonons from first principles

Daehyun Wee, Boris Kozinsky, Nicola Marzari, Marco Fornari

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67 Scopus citations

Abstract

We use ab initio computations to investigate the effect of filler ions on the properties of CoSb3 skutterudites. We analyze global and local structural effects of filling, using the Ba-filled system as an example. We show that the deformation of Sb network induced by the filler affects primarily nearest neighboring Sb sites around the filler site as the soft Sb rings accommodate the distortion. Rearrangement of Sb atoms affects the electronic band structure and we clarify the effect of this local strain on the band gap. We compute the phonon dispersions and identify the filler-dominated modes from the lowest-frequency optical modes at Γ. Their weak dispersion across the Brillouin zone indicates that they are localized and a force-constant analysis shows that the filler vibration is strongly coupled with nearby Sb atoms.

Original languageEnglish
Article number045204
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume81
Issue number4
DOIs
StatePublished - Jan 21 2010

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