The surface of the solid structures obtained by natural sedimentation from aqueous solutions of monodisperse Si${\mathrm{O}}_2$ spheres is imaged by atomic force microscopy. The dynamic scaling method applied to these images leads to temporal and spatial logarithmic scalings of the surface width that is consistent with the Edward-Wilkinson interface motion equation. It suggests that the interface grows close to equilibrium by the aggregation of Si${\mathrm{O}}_2$ spheres which, after reaching the growing surface driven by gravity, relax to minimum potential energy sites without significant attractive particle-particle interactions.

• Received 29 April 1996

DOI:https://doi.org/10.1103/PhysRevLett.77.4572