Formation of pyramids and mounds in molecular beam epitaxy
In: Physical Review / E, Statistical, nonlinear and soft matter physics, Jg. 53 (1996) ; Nr. 1, S. 307-318
ISSN: 1550-2376, 1539-3755
Zeitschriftenaufsatz / Fach: Physik
One of the generic scenarios in molecular beam epitaxy is the growth of three-dimensional structures such as mounds and pyramids. These structures are a nonequilibrium effect thought to be due to a combination of the microscopic Ehrlich-Schwoebel barriers and the breaking of detailed balance by the deposition process. We propose and investigate by computer simulation a simple microscopic model that displays (i) slope selection, (ii) pyramid and moundlike structures, and (iii) coarsening. The characteristic length scale of our three-dimensional features grows as R(t)∼tn with n between 0.17 and 0.26. We discuss these results in the light of recent experiments and continuum models of molecular beam epitaxy.