SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
CEA, DAM, DIF, 91297 Arpajon, France.
Phys Rev Lett. 2018 Aug 17;121(7):075002. doi: 10.1103/PhysRevLett.121.075002.
We present a new measurement of lattice disassembly times in femtosecond-laser-heated polycrystalline Au nanofoils. The results are compared with molecular dynamics simulations incorporating a highly optimized, embedded-atom-method interatomic potential. For absorbed energy densities of 0.9-4.3 MJ/kg, the agreement between the experiment and simulation reveals a single-crystal-like behavior of homogeneous melting and corroborates the applicability of the interatomic potential in the nonequilibrium warm dense matter regime. For energy densities below 0.9 MJ/kg, the measurement is consistent with nanocrystal behavior where melting is initiated at the grain boundaries.
我们提出了一种新的测量飞秒激光加热多晶金纳米薄片中晶格分解时间的方法。将实验结果与分子动力学模拟进行了比较，模拟中采用了高度优化的嵌入原子法原子间势。对于吸收能密度为 0.9-4.3 MJ/kg 的情况，实验和模拟之间的一致性表明了均匀熔化的单晶状行为，并证实了原子间势在非平衡温稠密物质状态下的适用性。对于低于 0.9 MJ/kg 的能量密度，测量结果与纳米晶体行为一致，其中熔化是从晶界开始的。
