Fig. 3: Observing the transition from 2D to 3D Coulomb interaction.
From: Slow and highly confined plasmons observed in atomically thin TaS2
a Experimental loss function (orange background) of 2H-TaS2 monolayers and b bilayers, extracted from the measured peak intensity and EELS differential loss probability after removing the EELS prefactor \(\sim {q}^{-3}\), assuming purely 2D Coulomb interaction (see Supplementary Note 2b). c Simulated loss function of 2H-TaS2 monolayer and d bilayer using Supplementary Eq. (16) with fitting parameters from Fig. 2b and an estimated damping rate \(\varGamma=0.4\) eV. White dashed lines in panels (a, b) represent the light line. The scatter and line plots in panel (c and d) are the dispersion relation taken from Fig. 2b. e Extracted EELS prefactor \({I}_{{kin}}\) in Eq. (3) for 2H-TaS2 monolayer and f bilayer from the fitted Lorentz–Drude amplitude after removing the interband screening factor \(1/{\varepsilon }_{{inter}}\left({{{\boldsymbol{q}}}}\right)\) in Eq. (3). The y-error bar for EELS prefactor is calculated from Eq. (3) using propagation of uncertainties. Dashed lines show fits to \({I}_{{kin}} \sim {q}^{-3}\) and \({q}^{-3}\), serving as visual guides for the 3D and 2D Coulomb regimes, respectively.
