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AAuAl (A = Ca, Sc, and Ti): Peierls Distortion, Atomic Coloring, and Structural Competition
Ames Laboratory Accepted Manuscripts
  • Joyce Pham, Iowa State University
  • Gordon J. Miller, Iowa State University and Ames Laboratory
Publication Date
Ames Laboratory; Chemistry
Report Number
IS-J 9640
Journal Title
Inorganic Chemistry

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.

Iowa State University Digital Repository, Ames IA (United States)
Citation Information
Joyce Pham and Gordon J. Miller. "AAuAl (A = Ca, Sc, and Ti): Peierls Distortion, Atomic Coloring, and Structural Competition" Vol. 57 Iss. 7 (2018) p. 4039 - 4049
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