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arXiv · 1602.00387

$\textit{Ab initio}$ evidence for nonthermal characteristics in ultrafast laser melting

Chao Lian·S. B. Zhang·Sheng Meng
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Abstract

Laser melting of semiconductors has been observed for almost 40 years; surprisingly, it is not well understood where most theoretical simulations show a laser-induced thermal process. $\textit{Ab initio}$ nonadiabatic simulations based on real-time time-dependent density functional theory reveal intrinsic nonthermal melting of silicon, at a temperature far below the thermal melting temperature of 1680 K. Both excitation threshold and time evolution of diffraction intensity agree well with experiment. Nonthermal melting is attributed to excitation-induced drastic changes in bonding electron density, and the subsequent decrease in the melting barrier, rather than lattice heating as previously assumed in the two-temperature models.

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Chao Lian, S. B. Zhang, Sheng Meng. 2016-02-01. $\textit{Ab initio}$ evidence for nonthermal characteristics in ultrafast laser melting. https://doi.org/10.1103/physrevb.94.184310

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