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arXiv · 2305.09531

Photoinduced dynamics of flat bands in the kagome metal CoSn

Denny Puntel·Wibke Bronsch·Manuel Tuniz·Mingu Kang·Paul M. Neves·Shiang Fang·Efthimios Kaxiras·Joseph G. Checkelsky·Riccardo Comin·Fulvio Parmigiani·Federico Cilento
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Abstract

CoSn is a prototypical kagome compound showing lattice-born flat bands with suppressed bandwidth over large parts of the Brillouin zone. Here, by means of time- and angle-resolved photoelectron spectroscopy, we provide direct evidence of the response to photoexcitation of the flat bands, that underlie information about localization in real space. In particular, we detect a sudden shift and broadening of the flat bands, while after one picosecond only a broadening survives. We ascribe both these effects to an ultrafast disruption of electron localization, which renormalizes the effective electron-electron interaction and affects the flat band dispersion. Since both variations are in the order of a few meV, our measurements suggest that the flat bands are resilient to near-infrared photoexcitation.

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Denny Puntel, Wibke Bronsch, Manuel Tuniz, Mingu Kang, Paul M. Neves, Shiang Fang, Efthimios Kaxiras, Joseph G. Checkelsky, Riccardo Comin, Fulvio Parmigiani, Federico Cilento. 2023-05-16. Photoinduced dynamics of flat bands in the kagome metal CoSn. https://arxiv.org/abs/2305.09531

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