Coalescence of the Fermi-surface-related diffuse-intensity peaks in disordered alloys

The theoretical possibility of the disappearance of the diffuse-intensity peak splitting induced by the Fermi surface in disordered alloys with decreasing temperature is predicted. The underlying mechanism is the compensation of the reciprocal-space curvatures of the self-energy and the interaction. The theory also describes similar results obtained earlier for two low-dimensional models with competing interactions. The coalescence is compared with the recently observed 'thermal' splitting in Pt-V which can be explained in the same way.