Melting curve of aluminum up to 300 GPa obtained through<i>ab initio</i>molecular dynamics simulations

Abstract

The melting curve of aluminum is determined up to 300 GPa using ab initio molecular dynamics simulations. The calculations are based on density functional theory within the generalized gradient approximation. We simulate the melting with two methods, the one-phase or heat until it melts and the two-phase approaches. The first one corresponds to a homogeneous melting, while the second one involves a heterogeneous melting of the materials. This conceptual difference gives rise to melting temperatures which can noticeably differ. As expected we observe a melting temperature overestimation in the one-phase approach compared to the two-phase approach. To reduce this overheating we use the hysteresis and the $Z$ method which try to combine the advantage of both techniques. We finally compare our theoretical data with experiments and we discuss the pertinence and the use of the methods.