Fig. 2: Stacking-dependent nano-IR spectroscopy of t-hBN.

a–c Spectra of the scattering amplitude ratios for three independent configurations averaged over AB, BA, and SP regions. The insets are near-field amplitude images of sample 1 at 1367.9 cm⁻¹ marking the regions used to construct spectra in the main panels (scale bars are 200 nm). d–f Spectra of nano-IR phase differences for three independent configurations averaged over AB, BA, and SP regions. The error bars in a–f equal the standard deviation (SD) from averaging amplitude and phase channels across pixels of identical stacking (see “Methods” for more details). All spectra are all simultaneously fit to the Lorentz model (Eq. (1)). The solid lines show the resulting fitting curves described in the text. g, h Spectra of the extracted dielectric functions. i The fitting parameters, with uncertainties on the last digit in parentheses (e.g., 1369.6(5) = 1369.6 ± 0.5), are reported in the table on the bottom right (all in units of wavenumbers). The uncertainties are taken to be the fitting parameters’ SD upon varying the initial guess parameters.