Picosecond-scale Heterogeneous Melting of Metals at Extreme Non-equilibrium States
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arXiv
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| Main Authors: | , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| _version_ | 1866918218074947584 |
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| author | Zeng, Qiyu Yu, Xiaoxiang Chen, Bo Zhang, Shen Chen, Kaiguo Kang, Dongdong Dai, Jiayu |
| author_facet | Zeng, Qiyu Yu, Xiaoxiang Chen, Bo Zhang, Shen Chen, Kaiguo Kang, Dongdong Dai, Jiayu |
| contents | Extreme electron-ion non-equilibrium states, generated by ultrafast laser excitation, lead to melting processes that are fundamentally different from those under conventional thermal equilibrium and remain not fully understood. Through neural network-enhanced multiscale simulations of tungsten and gold nanofilms, we identify electronic pressure relaxation as critical to heterogeneous phase transformations. This nonthermal expansion generates a density decrease that enable surface-initiated melting far below equilibrium melting temperatures, creating electronic pressure-driven solid-liquid interface propagation at a high speed of 2500 m/s -- tenfold faster than that of thermal heterogeneous melting mechanisms. Simulated time-resolved X-ray diffraction signatures distinguish this nonthermal expansion from thermal expansion dynamics driven by thermoelastic stress. These results establish hot-electron-mediated lattice destabilization as a universal pathway for laser-induced structural transformations, providing new insights for interpreting time-resolved experiments and controlling laser-matter interactions. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_20886 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Picosecond-scale Heterogeneous Melting of Metals at Extreme Non-equilibrium States Zeng, Qiyu Yu, Xiaoxiang Chen, Bo Zhang, Shen Chen, Kaiguo Kang, Dongdong Dai, Jiayu Computational Physics Materials Science Applied Physics Extreme electron-ion non-equilibrium states, generated by ultrafast laser excitation, lead to melting processes that are fundamentally different from those under conventional thermal equilibrium and remain not fully understood. Through neural network-enhanced multiscale simulations of tungsten and gold nanofilms, we identify electronic pressure relaxation as critical to heterogeneous phase transformations. This nonthermal expansion generates a density decrease that enable surface-initiated melting far below equilibrium melting temperatures, creating electronic pressure-driven solid-liquid interface propagation at a high speed of 2500 m/s -- tenfold faster than that of thermal heterogeneous melting mechanisms. Simulated time-resolved X-ray diffraction signatures distinguish this nonthermal expansion from thermal expansion dynamics driven by thermoelastic stress. These results establish hot-electron-mediated lattice destabilization as a universal pathway for laser-induced structural transformations, providing new insights for interpreting time-resolved experiments and controlling laser-matter interactions. |
| title | Picosecond-scale Heterogeneous Melting of Metals at Extreme Non-equilibrium States |
| topic | Computational Physics Materials Science Applied Physics |
| url | https://arxiv.org/abs/2502.20886 |