Molecular dynamics study on bulk melting induced by ultrashort pulse laser

• Published in: Journal of mechanical science and technology Vol. 25; no. 2; pp. 449 - 456
• Main Authors: Lee, Byoung Seo, Park, Seungho, Choi, Young Ki, Lee, Joon Sik
• Format: Journal Article
• Language: English
• Published: Heidelberg Korean Society of Mechanical Engineers 01.02.2011; Springer Nature B.V; 대한기계학회
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Control; Density; Dynamical Systems; Engineering; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Industrial and Production Engineering; Laser processing; Lasers; Liquid-solid interfaces; Mechanical Engineering; Mechanical engineering. Machine design; Melting; Molecular dynamics; Nucleation; Physics; Precision engineering, watch making; Solid-liquid transitions; Specific phase transitions; Vibration; 기계공학; Voronoi polyhedron; Bulk melting; Molecular dynamics simulation; Homogeneous nucleation; Molecular motion; Voronoï diagram; Liquid solid interface; Nucleation; Precision engineering; Laser assisted processing; Molecular dynamics; Sound velocity; Polyhedron; Ultrafast technique; Laser pulse; Holes; Modelling; Silicon; Kinetics; Dynamic model; Laser fusion; Structural analysis
• ISSN: 1738-494X; 1976-3824
• DOI: 10.1007/s12206-010-1226-2

Although many researches using nonthermal and thermal models have been conducted on ultrashort pulse laser processing, a promising tool for precision fabrication, an understanding of the underlying mechanism is still needed. The present study, in which molecular dynamics was carried out, accepted a thermal aspect as Tersoff model for silicon does not consider the nonthermal effect due to the electron-hole density. The kinetics of melting from the molecular motions was investigated by Voronoi polyhedron (VP) analysis as a structural tool. The results have shown that the ultrafast melting by the laser with 100 fs pulse is governed by bulk melting homogeneous nucleation. The bulk melting characteristics were revealed in the absence of liquid-solid interface, a melting speed excessively higher than the speed of sound, and kinetics consistent with that of the thermal model on homogeneous nucleation.