作者: Shuaishuai Sun , Zhongwen Li , Zi-An Li , Ruijuan Xiao , Ming Zhang
DOI: 10.1039/C8NR00432C
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摘要: Optical tuning and probing ultrafast structural response of nanomaterials driven by electronic excitation constitute a challenging but promising approach for understanding microscopic mechanisms applications in microelectromechanical systems optoelectrical devices. Here we use pulsed electron diffraction transmission microscope to investigate laser-induced tubular lattice dynamics multi-walled carbon nanotubes (MWCNTs) with varying laser fluence initial specimen temperature. Our photoexcitation experiments demonstrate cooperative inverse collective atomic motions intralayer interlayer directions, whose strengths rates depend on pump fluence. The electron-driven thermally responses opposite amplitudes cause crossover between directions. ab initio calculations support these findings reveal that electrons excited from π π* orbitals tube weaken the bonds while strengthening along radial direction. Moreover, MWCNTs at temperatures 300 100 K, uncover concomitance thermal nonthermal dynamical processes their mutual influence MWCNTs. results illustrate nature process electron–phonon thermalization MWCNTs, bear implications intricate energy conversion transfer materials nanoscale.