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arXiv · 2406.02998

Direct observation of the vanishing EELS cross section in graphene

Alberto Guandalini·Ryosuke Senga·Yung-Chang Lin·Kazu Suenaga·Paolo Barone·Francesco Mauri·Thomas Pichler·Christian Kramberger
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Abstract

In transmission electron energy-loss spectroscopy, the cross section in 2D is quenched by kinematic effects once the momentum transfer becomes smaller than a critical value set by $q_z$, the momentum loss parallel to the beam. Our highly momentum ($\Delta q = 0.02$~\r{A}$^{-1}$) and energy ($\Delta E = 45$~meV) resolved setup is instrumental on delivering the unprecedented experimental verification of quenched 2D EEL spectra on freestanding graphene at momentum transfers $q$ below $0.06$\r{A}$^{-1}$. We retrieve the intrinsic uniform dielectric response of graphene from measured spectra by quantifying the kinematic suppression.

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Alberto Guandalini, Ryosuke Senga, Yung-Chang Lin, Kazu Suenaga, Paolo Barone, Francesco Mauri, Thomas Pichler, Christian Kramberger. 2024-06-05. Direct observation of the vanishing EELS cross section in graphene. https://arxiv.org/abs/2406.02998

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