Explanation

surface phonon refers to the quantum of crystal surface that can be seen as quasi two-dimensional lattice, quasi two-dimensional lattice wave. When the surface of a solid medium is subjected to alternating surface tension, the particles undergo corresponding longitudinal and transverse composite vibrations. At this time, the wave propagation caused by the particle vibration only occurs on the surface of the solid medium, and the energy is concentrated within the surface of the solid, hence it is called surface acoustic wave (SAW). The elasticity medium theory is applicable to acoustic surface waves whose wave vector is much smaller than Brillouin boundary. When the local area of the surface wave is strong or the wavelength is short, the continuum theory is no longer applicable, and the surface shows the importance of surface phonon properties due to the reduction of symmetry.

Classification