Superlattices and long-range order in electrodeposited dendrites

We observe the spontaneous reemergence of long-range crystalline order in the electrochemical deposition of metal dendrites very far from equilibrium. This long-range order appears simultaneously with novel superlattice structures as revealed by high-resolution x-ray and electron diffraction. In order to explain these observations, we propose a simple picture, which we call the ``keystone model,'' for electrocrystallization in an aqueous environment.