Calculation of Short-Range-Order Diffuse Intensity for a Two Dimensional Square Lattice within Cluster Variation Method

Abstract

The Cluster Variation Method (CVM) within the square approximation is employed to calculate Short-Range-Order diffuse intensity spectrum for a binary alloy in a two dimensional square lattice. The peak intensity at 1:1 stoichiometric composition is attained at (kx,ky)=(0.5,0.5) in the k-space. The instability temperature determined by the calculation of the Short-Range-Order diffuse intensity coincides with the phase boundary, indicating that the transition is of second-order. The integrated intensity in a Brillouin zone is also calculated to examine the level of the approximation