Landau-Ginzburg theory of order-disorder transition in semi-infinite systems

Abstract

The parameters of the Landau-Ginzburg functional for atomic order-disorder transitions are calculated from a microscopic Ising-like Hamiltonian. It is shown that the surface force ${\lambda }^{-1\mathrm{}}$ and the transition depend crucially on segregation at the surface. It is shown that the surface may order before ordering in the bulk occurs.