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Linear Metal Chains in Ca2M2X (M = Pd, Pt; X = Al, Ge): Origin of the Pairwise Distortion and Its Role in the Structure Stability

TitleLinear Metal Chains in Ca2M2X (M = Pd, Pt; X = Al, Ge): Origin of the Pairwise Distortion and Its Role in the Structure Stability
Publication TypeJournal Article
Year of Publication2015
AuthorsDoverbratt, I, Ponou, S, Zhang, YM, Lidin, S, Miller, GJ
JournalChemistry of Materials
Volume27
Pagination304-315
Date Published01
Type of ArticleArticle
ISBN Number0897-4756
Accession NumberWOS:000348085300038
Keywordsaugmented-wave method, calculations, coloring problem, crystal-structure, magnetic-properties, physical-properties, polar intermetallic phase, preference, rare-earth, site, ternary gold polyphosphides, total-energy
Abstract

allic properties are predicted by TB-LMTO calculations. In contrast, the isoelectronic Ca2Pt2Ge is predicted to be a good metal with the Fermi level located at a local maximum of the DOS, a fingerprint of potential electronic instability. This is due to greater charge transfer to the more electronegative Pt atoms forming the metal chains and probably to packing frustration in the well packed structure that may prevent a larger distortion of the Pt chains. However, the instability is suppressed in the aliovalent but isostructural phases Ca2M2Al (27 ve/f.u) with an enhancement of the pairing distortion within the metal chains but lower M-M bond order. Further reduction of the vec as in Ca2M2Cd (26 ve/f.u) may induce a transition toward the more geometrically flexible W2CoB2-type with a low dimensional structure, to create more room for a larger distortion of the metal chain as dictated by the shortage of valence electrons.

DOI10.1021/cm503985h
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