论文标题
非热金属化动力学对化合物键离子的依赖性
Dependence of nonthermal metallization kinetics on bond ionicity of compounds
论文作者
论文摘要
众所周知，在电子系统的超快激发时，共价键合的材料会经历非热结构转换，而金属则表现出声子硬化。在这里，我们研究离子键如何对电子激发反应。密度功能的分子动力学预测，与共价材料相反，离子晶体可能非热融化为电子绝缘态。我们证明，非热过渡过程中的带隙行为取决于键合类型：更难使较大离子化合物中的带隙折叠，这是通过Y2O3中的转换与NaCl，LIF和KBR所说的。
It is known that covalently bonded materials undergo nonthermal structure transformations upon ultrafast excitation of an electronic system, whereas metals exhibit phonon hardening. Here we study how ionic bonds react to electronic excitation. Density-functional molecular dynamics predicts that ionic crystals may melt nonthermally, however, into an electronically insulating state, in contrast to covalent materials. We demonstrate that the band gap behavior during nonthermal transitions depends on a bonding type: it is harder to collapse the band gap in more ionic compounds, which is illustrated by transformations in Y2O3 vs. NaCl, LiF and KBr.
