Nanowire melting modes during the solid-liquid phase transition: theory and molecular dynamics simulations

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Nanowires exhibit unique melting behaviors distinct from bulk materials.
• Surface melting is an initial step preceding bulk melting in nanowires.
• Two primary mechanisms, interface recession and instability-driven breakup, govern nanowire melting.

Purpose of the Study:

• To elucidate the preferred melting mechanisms in nanowires.
• To determine the critical factors influencing the transition between melting mechanisms.
• To validate theoretical models against molecular dynamics simulations.

Main Methods:

• Perturbation of a capillary fluctuation model for interface kinetics.
• Comparison of theoretical predictions with molecular dynamics simulations.
• Analysis of instability growth and interface front propagation.

Main Results:

• A Plateau-Rayleigh-type instability governs nanowire breakup.
• Melting mechanism is length-dependent: longer nanowires favor instability, shorter ones favor interface recession.
• Simulation results align with theoretical predictions regarding preferred melting modes.

Conclusions:

• Nanowire melting is dictated by a competition between interface kinetics and instability growth.
• Wire length is a critical parameter determining whether melting proceeds via breakup or interface recession.
• The study provides a theoretical framework for understanding nanowire thermal stability.