It was demonstrated, using computer simulations based upon deterministic kinetic equations and Monte Carlo techniques that, during intermixing in an ideal AB system with an initially wide A/B interface, the interface could become sharp at the nanoscale; if the diffusion coefficient depended strongly upon the concentration. The sharp interface shifted linearly with time (in contrast to a square-root law). It was also shown that, at the beginning of intermixing in a finite bilayer or in multilayers, a decrease in the concentration gradient occurred by the filling-up of one of the initially pure layers and by a shift of the sharpening interface.

Interface Sharpening instead of Broadening by Diffusion in Ideal Binary Alloys. Z.Erdélyi, I.A.Szabó, D.L.Beke: Physical Review Letters, 2002, 89[16], 165901 (4pp)