#figure( image("/画图/声子不连续/embed.svg"), caption: [ (a) Phonon dispersion of 4H-SiC along the A–#sym.Gamma–K high-symmetry path. Gray lines represent negligible-polar phonon modes, while colored lines indicate strong-polar phonon modes. The green, red and blue lines indicate the mode along the z-direction, y-direction and x-direction, respectively. Along A-#sym.Gamma path, strong-polar modes along x- and y-directions are degenerated, showing as a single purple line. (b) Magnified view of the boxed region in (a). The orange dashed lines mark the phonon wavevectors involved in Raman scattering with incident light along the z- and y-directions. ], placement: none, )