Surface critical behavior of bcc binary alloys
Abstract
The surface critical behavior of bcc binary alloys undergoing a continuous B2-A2 order-disorder transition is investigated in the mean-field (MF) approximation. Our main aim is to provide clear evidence for the fact that surfaces which break the two-sublattice symmetry generically display the critical behavior of the NORMAL transition, whereas symmetry-preserving surfaces exhibit ORDINARY surface critical behavior. To this end we analyze the lattice MF equations for both types of surfaces in terms of nonlinear symplectic maps and derive a Ginzburg-Landau model for the symmetry-breaking (100) surface. The crucial feature of the continuum model is the emergence of an EFFECTIVE ORDERING (``staggered'') SURFACE FIELD, which depends on temperature and the other lattice model parameters, and which explains the appearance of NORMAL critical behavior for symmetry-breaking surfaces.
Keywords
Cite
@article{arxiv.cond-mat/9707345,
title = {Surface critical behavior of bcc binary alloys},
author = {R. Leidl and H. W. Diehl},
journal= {arXiv preprint arXiv:cond-mat/9707345},
year = {2009}
}
Comments
16 pages, REVTeX 3.0, 13 EPSF figures, submitted to Phys. Rev. B