On the basis of a new first-principles, electronic model for the forces driving clustering and short-range order in metallic alloys, it is argued that observed concentration-dependent peaks in the x-ray and electron diffuse scattering intensities are due to parallel sheets of flat Fermi surface. The positions of the peaks are directly related to the spanning vector ${\overrightarrow{\mathrm{k}}}_0$.

• Received 18 June 1982

DOI:https://doi.org/10.1103/PhysRevLett.50.374