LAUSR

Abstract We have calculated the quasiparticle particle self-energy and spectral function in a graphene plane when a symmetry breaking of the sublattice is occurred. Holstein model Hamiltonian has been applied to describe the electron dynamics in the presence of lattice vibrations. This model Hamiltonian takes into account the effects of interaction between electrons and Einstein phonons beyond the usual Dirac-cone approximation. Specially, the effects of gap parameter and electron-phonon coupling strength on spectral function, inelastic scattering lifetime and band gap renormalization have been studied. Also the electron density dependence of inelastic scattering lifetime for different values of gap parameter has been investigated. In order to find the quasiparticle excitation spectrum of the interacting electronic system, we have studied the frequency dependence of spectral function for different physical parameters. Our results show the intensity of broad peak in frequency dependence of spectral function reduces with electron-phonon coupling strength. However the intensity of quasiparticle particle peak increases with coupling strength. The increase of gap parameter leads to appear sharp quasiparticle peak with high intensity in spectral function. The frequency dependence of sharp peak goes to higher frequency with gap parameter. Also the gap parameter dependence of inverse of scattering life time shows a sudden change for all values of coupling constant. Finally band gap renormalization enhances with electron-phonon coupling constant at fixed electron density.