We study the collective diffusion in chain structures on anisotropic substr
ates like (1 1 2)bcc and (1 1 0)fcc surfaces with deep troughs in the subst
rate potential corrugation. These chain structures are aligned normal to th
e troughs and can move only along the troughs. In a combination of theoreti
cal arguments and of numerical simulations, we study the mass transport in
these anisotropic systems. We find that a mechanism similar to soliton diff
usion, instead of single particle diffusion, is still effective at temperat
ures well above the melting temperature of the ordered chain structures. Th
is mechanism is directly correlated with the ordered phases that appear at
much lower temperatures. As a consequence. also the influence of frozen dis
order is still visible above the melting temperature. Theoretically we pred
ict a strong dependence of the pre-exponential factor and weak dependence o
f the activation energy on the concentration of frozen surface defects. The
se predictions are confirmed by the simulations. (C) 2001 Published by Else
vier Science B.V.