Figure 1

The velocity of the melting front propagation in EAM Ni crystal as a function of the overheating. The results of MD simulations performed at constant lattice temperature maintained throughout the system are shown by diamonds. The solid line is a guide to the eye. The vertical dashed line marks the value of overheating above which homogeneous nucleation of liquid regions inside the superheated crystal is observed. The velocities of the melting front in the simulations where both homogeneous and heterogeneous melting is observed are shown by open diamonds. Dark gray (red) circles show the velocities of the melting front in TTM-MD simulations where constant electron temperature is maintained in the bulk of the system and the temperature at the melting front is defined by the transfer of the lattice thermal energy to the latent heat of melting, the electron heat conduction from the bulk, and the electron-phonon coupling (see text for details). The data points shown by dark gray (red) circles are for temperatures of the bulk; if values of local temperatures at the melting front are used (see Fig. 2) the points shift closer to the results obtained in simulations with enforced constant temperature, as shown for a simulation performed at a bulk temperature of $1.19T_m$ by a dashed arrow.Reuse & Permissions

Figure 2

Lattice and electron temperature distributions in a TTM-MD simulation of an overheated crystal with a melting front propagating from a free surface. The lattice and electron temperatures are shown by solid and dashed lines, respectively. Constant temperature of $1.19T_m$ is maintained at the depth of 100 nm under the surface.Reuse & Permissions

Figure 3

Snapshots taken at different times during the TTM-MD simulation illustrated by Fig. 2. The melting starts at the free surface (at the bottom) and the melting front propagates upward, deeper into the bulk of the crystal. The crystalline part of the system is blanked whereas the liquid is shown in dark gray (blue). The solid-liquid interface, shown in light gray (green), is identified using the local order parameter [12] averaged over 1 nm cubic cells. The position of the solid-liquid interface within a partially melted cell is defined based on the amount of liquid phase in the cell.Reuse & Permissions

Figure 4

Deviation of the surface area of the solid-liquid interface, $A_{s\mathrm{\text{−}}l}$, from the one of a perfect plane, $A_p$, shown as a function of the overheating. The line is a linear fit to the data points.Reuse & Permissions