Stability and instability of long-period superstructures in binary Cu–Pd alloys: A first principles study

✍ Scribed by Stefan Bärthlein; Elke Winning; Gus L.W. Hart; Stefan Müller

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 722 KB
• Volume: 57
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2008.12.013

✦ Synopsis

Whereas binary intermetallic compounds often appear as ordered structures with fewer than 10 atoms per cell, large-supercell structures consisting of one-and two-dimensional superstructures have long been observed in CuPd. However, whereas the stability of the ordinary one-dimensional long-period superstructures (1-D LPS) has been previously investigated by first-principles total-energy methods, two-dimensional superstructures were not amenable to such calculations because of their large number of atoms (O(10 3 ) atoms/cell). Using a cluster expansion extracted from a set of first-principles total energy calculations, we show that 2-D LPSs are likely kineticallystabilized structures which transform into the 1-D LPS ground-state structures at thermodynamic equilibrium.