Publication Date

3-16-2018

Department

Ames Laboratory; Chemistry

Campus Units

Chemistry, Ames Laboratory

Report Number

IS-J 9640

DOI

10.1021/acs.inorgchem.8b00214

Journal Title

Inorganic Chemistry

Volume Number

57

Issue Number

7

First Page

4039

Last Page

4049

Abstract

Using density functional theory, the crystal structure variation of AAuAl (A = Ca, Sc, and Ti) from orthorhombic Co2Si-type to distorted hexagonal Fe2P-type and then Ni2In-type structures is shown to correlate with their electronic struc-tures and valence electron counts, sizes of the active metals A, and site preferences for Au and Al atoms, which are arranged to maximize Au−Al nearest neighbor contacts. An evaluation of chemical pressure imposed by the varying A metals using total energy vs. volume calculations indicates that larger unit cell volumes favor the orthorhombic structure whereas smaller vol-umes favor the hexagonal structures. The electronic origin of the Mg2Ga-type crystal structure of ScAuAl, refined as a distorted Fe2P-type supercell doubled along the c-axis, indicates a Peierls-type distortion mechanism of the Au-chains along the c-axis.

Language

en

Department of Energy Subject Categories

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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