Regensburg 1998 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

M: Metallphysik

M 19: Elektronische Strukturen und Eigenschaften I

M 19.4: Vortrag

Mittwoch, 25. März 1998, 15:30–15:50, H 33

Phase stability of Cu_xZn_yAl_100−x−y alloys — •V. Crişan¹, H. Ebert¹, P. Entel², and H. Akai³ — ¹Institut f"ur Physikalische Chemie, Universit"at M"unchen, Theresienstr. 37, 80333 M"unchen — ²Theoretische Physik, Gerhard-Mercator-Universität Duisburg,47048 Duisburg — ³Department of Physics, Osaka University, 1-16 Machikaneyama, Toyonaka, Osaka 560, Japan

Total energy calculations for Cu_xZn_yAl_100−x−y random alloys were done for both the FCC and BCC structure for the hole concentration range. The most stable alloys were found for small Al concentrations and the most unstable ones in the middle of the phase diagram. The Al atoms produce no extra bonding but favorized the FCC structure against the BCC structure. The lattice parameters, determined from the total energy calculations, increase with the concentration parameter y with a slope depending on x. In the limit of x=0; for Zn_yAl_100−y the stability of the system against concentration waves was establish from total energy calculations using supercells. This way the presence of a small vacancy concentration, at the small waves length limit, could be accounted for. For some alloys the Fermi surface was investigated by calculating the the Bloch spectral functions at the Fermi energy. All calculations were done using the fast KKR-CPA method in the scalar-relativistic approximation together with the GGA-form for the exchange and correlation potential and energy.