Fig. 3: Comparison of LO phonon of monolayer h-BN on Cu foil and Cu single crystal substrates.
From: Observation of the nonanalytic behavior of optical phonons in monolayer hexagonal boron nitride
a 2D phonon spectra of the LO phonon of h-BN/Cu foil. b LO phonon dispersion data of h-BN/Cu foil extracted from EDC. c A schematic of the morphology of the monolayer h-BN/Cu foil. d–f Results for monolayer h-BN/Cu crystal corresponding to a–c. The dashed curves in a, b, d, and e are guides to the eye. The height of the gray shaded areas in b and e represent the full width at half maximum (FWHM) of the zero-loss peak, reflecting the energy uncertainty of the measured data. Note that the weak intensity around 185 meV at the CBZ in d is contributed by the adsorption vibration of carbon62, which does not affect the results, as discussed in detail in Supplementary Fig. S7 in the SI.
