Author(s): Liu, WH (Liu, Wen-Hao); Luo, JW (Luo, Jun-Wei); Li, SS (Li, Shu-Shen); Wang, LW (Wang, Lin-Wang)

Source: SCIENCE ADVANCES Volume: 8 Issue: 27 Article Number: eabn4430 DOI: 10.1126/sciadv.abn4430 Published: JUL 8 2022

Abstract: Laser-induced nonthermal melting in semiconductors has been studied over the past four decades, but the underlying mechanism is still under debate. Here, by using an advanced real-time time-dependent density functional theory simulation, we reveal that the photoexcitation-induced ultrafast nonthermal melting in silicon occurs via homogeneous nucleation with random seeds originating from a self-amplified local dynamic instability. Because of this local dynamic instability, any initial small random thermal displacements of atoms can be amplified by a charge transfer of photoexcited carriers, which, in turn, creates a local self-trapping center for the excited carriers and yields the random nucleation seeds. Because a sufficient amount of photoexcited hot carriers must be cooled down to band edges before participating in the self-amplification of local lattice distortions, the time needed for hot carrier cooling is the response for the longer melting time scales at shorter laser wavelengths. This finding provides fresh insights into photoinduced ultrafast nonthermal melting.

Accession Number: WOS:000823446300016

PubMed ID: 35857455

ISSN: 2375-2548

Full Text: https://www.science.org/doi/10.1126/sciadv.abn4430