MOLECULAR-DYNAMICS STUDY OF THE LOCAL SYMMETRY CHANGES IN METALLIC LIQUIDS

It has been conjectured that the local structure of simple mono-atomic liquids is mainly of ve-fold symmetry. Experimental evidence for such icosahedral building blocks has recently been found in liquid droplets of lead adjacent to a silicon wall and in deeply undercooled melts of pure metallic elements like bcc iron, fcc nickel and bcc zir-conium. We have used molecular dynamics in order to investigate supercooling eects in the melt of another pure element (aluminum) on the basis of a common neighbor analysis. In the simulation we have employed an embedded atom method potential optimized with the help of ab initio calculations for aluminum. The simulations con-rm the recent experimental results that, independent of the system, the icosahedral short-range order strongly increases with the degree of undercooling