Phase diagram of Cu-Au-type alloys |
| |
Authors: | Joel L Lebowitz Mohan K Phani Daniel F Styer |
| |
Institution: | (1) Departments of Mathematics and Physics, Rutgers University, 08903 New Brunswick, New Jersey;(2) Present address: Department of Physics, Indian Institute of Science, 560012 Bengalore, India |
| |
Abstract: | We investigate the ordering phase diagram of an binary alloy on a face centered cubic lattice. In Ising spin language the nearest-neighbor interactions are antiferromagnetic with strengthJ, the next-nearest-neighbor interactions are ferromagnetic with strength J, and the external magnetic field ish. For > 0 and allh, the ground state is only finitely degenerate, so Pirogov-Sinai theory gives the exact form of the phase diagram in the limit of vanishing temperature. For=0 and vhv 12J the ground state is infinitely degenerate, and indeed the zero temperature entropy is nonvanishing at the four super-degenerate pointsh=± 47 or ±1Z7. We investigate the finite temperature behavior of the model using Monte Carlo simulations and (for=0) low temperature expansions. The most interesting portions of the phase diagram are those near the superdegenerate points. We rigorously map these points onto certain hard constraint lattice gases, but can draw no firm conclusions concerning the phase diagram in their vicinity.Supported in part by the National Science Foundation through Grant No. DMR81-14726. The simulations were carried out at the Center for Materials Science at Los Alamos National Laboratory. |
| |
Keywords: | Ising models face centered cubic lattice binary alloys phase diagrams frustration first-order phase transitions |
本文献已被 SpringerLink 等数据库收录! |
|