Surface plasmon of three-dimensional Dirac semimetals

The surface plasmon excitation spectrum is calculated for the semi-infinite 3D Dirac semimetal. We used the-random phase approximation for the calculation of the-surface-dielectric function, from which we derived the dynamical structure factor. The surface-excitation spectrum shows a well-defined strong surface plasmon peak due to the plasmon mode in the bulk, with a noticeable influence of electron-hole excitations at large wave vectors parallel to the surface. The-obtained spectrum will be useful for experimentally exploring the surface spectral properties of 3D topological Dirac semimetals.