Investigation of electron-phonon coupling in epitaxial silicene byin situRaman spectroscopy

We report that the special coupling between Dirac fermion and lattice vibrations, in other words, electron-phonon coupling (EPC), in silicene layers on an Ag(111) surface was probed by in situ Raman spectroscopy. We find the EPC is significantly modulated due to tensile strain, which results from the lattice mismatch between silicene and the substrate, and the charge doping from the substrate. The special phonon modes corresponding to two-dimensional electron gas scattering at the edge sites in the silicene were identified. Detecting the relationship between EPC and Dirac fermions through Raman scattering will provide a direct route to investigate the exotic property in buckled two-dimensional honeycomb materials.