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arXiv · 2209.12135

Origin of Immediate Damping of Coherent Oscillations in Photoinduced Charge Density Wave Transition

Yu-Xiang Gu§·Wen-Hao Liu§·Zhi Wang·Shu-Shen Li·Lin-Wang Wang·Jun-Wei Luo
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Abstract

In stark contrast to the conventional charge density wave (CDW) materials, the one-dimensional CDW on the In/Si(111) surface exhibits immediate damping of the CDW oscillation during the photoinduced phase transition. Here, by successfully reproducing the experimentally observed photoinduced CDW transition on the In/Si(111) surface by performing real-time time-dependent density functional theory (rt-TDDFT) simulations, we demonstrate that photoexcitation promotes valence electrons from Si substrate to empty surface bands composed primarily of the covalent p-p bonding states of the long In-In bonds, generating interatomic forces to shorten the long bonds and in turn drives coherently the structural transition. We illustrate that after the structural transition, the component of these surface bands occurs a switch among different covalent In bonds, causing a rotation of the interatomic forces by about {\pi}/6 and thus quickly damping the oscillations in feature CDW modes. These findings provide a deeper understanding of photoinduced phase transitions.

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Yu-Xiang Gu§, Wen-Hao Liu§, Zhi Wang, Shu-Shen Li, Lin-Wang Wang, Jun-Wei Luo. 2022-09-25. Origin of Immediate Damping of Coherent Oscillations in Photoinduced Charge Density Wave Transition. https://doi.org/10.1103/physrevlett.130.146901

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