The order-disorder transition at the surface of an fcc Ising antiferromagnet with nearest- and next-nearest-neighbor interactions which exhibits an L$1_2$ ($A_3$B) ground-state structure is studied using Monte Carlo and renormalization-group methods. Monte Carlo results for the surface phase diagram, critical behavior of both excess and local quantities, as well as the short-range-order parameter at the surface are presented. The critical behavior is shown to be consistent with the predictions of mean-field theory.

• Received 11 January 1988

DOI:https://doi.org/10.1103/PhysRevB.38.459