Driving forces for ultrafast laser-induced sp2 to sp3 structural transformation in graphite
Driving forces for ultrafast laser-induced sp2 to sp3 structural transformation in graphite
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DOI：
10.1038/s41524-023-01035-2
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发表时间：
2023-05-22
影响因子：
9.7
通讯作者：
Meng, Sheng
中科院分区：
文献类型：
--
作者：
Song, Chenchen;Guan, Mengxue;Meng, Sheng
理解石墨中sp（2）-到sp（3）结构光致转变的微观机制是一个具有重要意义的科学挑战。本文采用非绝热量子动力学模拟方法，揭示了激光诱导石墨结构转变的超快动力学过程及其特征。在激光辐照下，石墨经历了层间压缩和滑动阶段，然后经历了层内屈曲和层间键合的关键阶段，形成了sp（2）-sp（3）的中间杂化结构，最后完全转变为六方金刚石。该过程是由电荷载流子倍增和通过电子-声子相互作用的选择性声子激发的合作驱动的，其中光激发的热电子散射到未被占据的高能导带中在石墨中引入面内不稳定性中起关键作用。这项工作确定了从石墨到金刚石的光致非绝热转变途径，并对材料中的光控结构相变设计产生了深远的影响。
Understanding the microscopic mechanism of photoinduced sp(2)-to-sp(3) structural transformation in graphite is a scientific challenge with great importance. Here, the ultrafast dynamics and characteristics of laser-induced structural transformation in graphite are revealed by non-adiabatic quantum dynamic simulations. Under laser irradiation, graphite undergoes an interlayer compression and sliding stage, followed by a key period of intralayer buckling and interlayer bonding to form an intermediate sp(2)-sp(3) hybrid structure, before completing the full transformation to hexagonal diamond. The process is driven by the cooperation of charge carrier multiplication and selective phonon excitations through electron-phonon interactions, in which photoexcited hot electrons scattered into unoccupied high-energy conduction bands play a key role in the introduction of in-plane instability in graphite. This work identifies a photoinduced non-adiabatic transition pathway from graphite to diamond and shows far-reaching implications for designing optically controlled structural phase transition in materials.