  In this letter, we report that the special coupling between Dirac fermion and
lattice vibrations, in other words, electron-phonon coupling (EPC), in silicene
layers on Ag(111) surface was probed by an 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 edge sites in the silicene were identified.
Detecting relationship between EPC and Dirac fermion through the Raman
scattering will provide a direct route to investigate the exotic property in
buckled two-dimensional honeycomb materials.
