Photoemission time delay at giant plasmon excitations of a selection of fullerenes: size and symmetry

Large-scale coherent electron correlations driven by extreme ultraviolet light play the dominant role to induce a giant plasmon excitation (GPE) in fullerene molecules. This excitation primarily decays through the degenerate ionization channels creating a strong and broad resonance in the photoelectron spectrum. The underlying many-body mechanism drives a transient attractive force to affect a significant time delay of the photoelectrons to reach the detector. In order to simulate this intrinsic delay, the Eisenbud-Wigner-Smith (EWS) time delay, we apply linear response time-dependent density functional theory [1,2] to a selection of fullerene molecules at GPE energies. Comparisons reveal a systematic effect of the fullerene size. Further comparisons with our pump-probe streaking measurements of C₆₀ [3] and C₇₀ suggest effects of the deviation from spherical symmetry on the time delay.

[1] J. Choi, E.H. Chang, D.M. Anstine, M.E. Madjet, and H.S. Chakraborty, Phys. Rev. A 95, 023404 (2017).

[2] M. Magrakvelidze, M.E. Madjet, G. Dixit, M. Ivanov, and H.S. Chakraborty, Phys. Rev. A 91, 063415 (2015).

[3] S. Biswas, A. Trabattoni, P. Rupp, M. Magrakvelidze, M.E. Madjet……H.S. Chakraborty, M.F. Kling, and F. Calegari, Science Advances (in press).