Picosecond-scale heterogeneous melting of metals at extreme non-equilibrium states

作者：Qiyu Zeng, Xiaoxiang Yu, Bo Chen, Shen Zhang, Kaiguo Chen, Dongdong Kang, Jiayu Dai · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-65485-6 · 被引用次数：10 · 研究领域：nanoparticles nucleation surface interactions、Machine Learning in Materials Science、Laser Material Processing Techniques

Abstract 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 ms −1 —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.