Atomic ordering in the liquid adjacent to an atomically rough solid surface

In this work, atomic ordering in the liquid adjacent to both crystalline and amorphous substrates with atomic level surface roughness was investigated systematically using molecular dynamics (MD) simulations. We found for the first time that increasing surface roughness of a crystalline substrate reduces both atomic layering and in-plane atomic ordering in the metallic liquid adjacent to the liquid/substrate interface. In addition, our MD simulation results revealed that the rough surface of an amorphous substrate eliminates completely in-plane ordering in the liquid regardless of surface roughness and reduces/eliminates atomic layering in the liquid depending on the level of surface roughness. This reduced atomic ordering in the liquid adjacent to an atomically rough surface can be attributed to the increase in mobility of atoms in the liquid compared with the case with a smooth crystalline surface. From the point of view of heterogeneous nucleation, in addition to the effect of lattice misfit investigated in our previous studies, this work provides further confirmation of the importance of structural templating as a mechanism for both prenucleation and heterogeneous nucleation. Furthermore, this work offers a new approach to impede heterogeneous nucleation by roughening the substrate surface at the atomic level.