Fig. 2: Experimental and computational energy-momentum dispersion maps of plasmons and excitons in hBN.
a Energy-momentum (ωq) map (log scale) of hBN in Γ → M showing the dispersion of both, π (white arrow) and π + σ plasmon peaks across the Brillouin Zone (BZ). b TDDFT maps of the energy-momentum dispersion of the main plasmon peaks along Γ → M for hBN showing quantitative agreement with experiments. c q-EEL spectra as extracted from a (boxed region) show that the π and π + σ peaks shift to higher energies with increasing |q| (up to |qmax| = 0.5 × |Γ − Γ′|). d ωq map (log scale) of hBN in Γ → K direction showing the dispersion of both, π (white arrow) and π + σ plasmon peaks across the BZ. e TDDFT maps of energy-momentum dispersion relations of plasmon peaks for hBN along Γ → K showing quantitative agreement with experiments. f The q-EEL spectra as extracted from a (boxed region) show that the π and π + σ peaks shift to higher energies with increasing |q| (up to |qmax| = 0.5 × |Γ − Γ'′|).
