Physical Review Letters, 1 May 1995, vol.74, (no.18):3632-5.
Simultaneous bunching and debunching of surface steps: theory and
relation to experiments.
Kandel, D.; Weeks, J.D.
We study a model of two-dimensional step flow where the velocity of a
step depends predominantly on the width of the terrace remaining behind
it. While the uniform step train is unstable towards step bunching, the
bunches themselves are unstable and tend to debunch. This leads to
patterns where slow moving fairly straight bunches coexist with fast,
strongly bent single steps, in qualitative agreement with experiments on
electric current driven step motion on Si(111) surfaces. Analytical
predictions of the shape and velocity of the single steps agree very well
with Monte Carlo simulations.
PDF file (151 KB).