Recoil effects in high energy photoemission of solids − Revisited

This study systematically investigates core level recoil in photoemission from crystalline silicon (Si) and silicon carbide (4H-SiC), within the X-ray range of 2.45–9.5 keV. By examining the Si 2p, 2s, and C 1s core levels, we observe that SiC exhibits energy shifts exceeding single-atom recoil predictions, along with a lineshape change at higher photon energies attributed to being phonon-induced. In contrast, pure Si shows more modest shifts and line broadening, consistent with expected recoil effects. These observations imply that especially compound materials, such as SiC, exhibit an enhanced interplay of recoil and phonon dynamics, underscoring the necessity for refined photoemission models that accommodate these effects.