Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MM: Metall- und Materialphysik
MM 33: Symposium Materials Modelling II
MM 33.6: Vortrag
Donnerstag, 30. März 2006, 16:15–16:30, IFW A
High-precision mixed-space cluster expansion for Cu-rich Cu-Pd alloys: Controlling the LPS group — •S. Bärthlein1, G.L.W. Hart2, A. Zunger3, and S. Müller1 — 1Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen — 2Department of Physics and Astronomy, Northern Arizona University, Flagstaff, Arizona 86011-6010 — 3National Renewable Energy Laboratory, Golden, Colorado 80401
A remarkable feature of Cu-Pd alloys is the existence of long-periodic superlattices (LPS) on the Cu-rich side of the phase diagram. Whereas earlier studies did not include necessary information about the diversity of important, but until then inaccessible formation enthalpies, we are able by combining DFT calculations with a mixed-space cluster expansion, genetic algorithms [1] and Monte Carlo to predict the phase stability from millions of possible candidates. Effective interactions were constructed, enabling us to predict and to study the realm of one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) LPS with 1D-LPS3 being the T=0K ground state at xPd=0.25. Furthermore, we investigate the so-called “L12” phase, which emerges as a domain-mixture between the LPS3 and a newly discovered low-temperature phase at xPd=0.125. Examination of the systems short-range order reveals a continuous transition from the domain-mixture to the disordered solid solution. (Supported by DFG and NSF.)
[1] G.L.W. Hart et al., Nat. Mater. 4, 391 (2005)