Ab initio study of W-Al-Co-Ni: An approximant of the decagonal Al-Co-Ni quasicrystal

Kai H. Hassdenteufel, Artem R. Oganov, Sergiy Katrych, Walter Steurer

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8 Citations (Scopus)

Abstract

We have performed ab initio simulations of binary and ternary periodic model structures based on the W phase in order to investigate chemical bonding, its response to pressure, and structural relaxations accompanying the substitution of Co by Ni. Our results support previous conclusions that the maximization of Al-Co and Ni-Ni interactions is favorable for reaching the lowest-energy state. The valence electron localization function (ELF) indicates partially covalent bonding supporting the formation of energetically favorable atomic clusters. The existence of a pseudogap in the calculated electronic density of states close to the Fermi level suggests electronic stabilization according to the Hume-Rothery-type mechanism. High-pressure simulations of binary W-(Al,Co) up to 90 GPa reveal increasing puckering of the atomic layers perpendicular to the pseudotenfold b axis. Furthermore, the basic pentagonal columnar clusters become distorted, leading to shorter distances between neighboring Co atoms. The structural changes in the vicinity of the distorted clusters point to local changes in the chemical bonding as reflected in the valence ELF.

Original languageEnglish
Article number144115
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume75
Issue number14
DOIs
Publication statusPublished - 30 Apr 2007
Externally publishedYes

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