Structural complexity in binary bcc ground states: The case of bcc Mo-Ta

Journal Article

Traditional sorting diagrams for ground states (T=0 stable atomic configurations) of bcc-based binary alloys predict simple crystal structures when simple parametric interactions (e.g., first few pairs) are assumed. However, the range and magnitude of interactions for real systems is not a priori known, and could lead to much greater structural complexity. We combine a density functional theory based, deterministic mixed-basis cluster expansion with an exhaustive enumeration scheme of 3 × 106 possible structures to determine the ground states of the bcc alloy Mo-Ta. The result is a rich ground-state line, changing one's outlook on bcc structural stability. We find Mo-rich (100) superlattices (including C11b and B2) coexisting with complex large-cell structures (Mo4Ta9. We demonstrate that a systematic cluster expansion construction scheme which includes both high-order pairs and many-body figures is a necessity to capture the ground states of Mo-Ta.

Duke Authors

Cited Authors

  • Blum, V; Zunger, A

Published Date

  • 2004

Published In

Volume / Issue

  • 69 / 2

Start / End Page

  • 201031 - 201034

International Standard Serial Number (ISSN)

  • 0163-1829