Path-integral theory for photoemission spectra of electron-phonon coupled system

Kai Ji

Institute of materials structure science, High energy accelerator research organization, 305-0801, Tsukuba, Japan

Using a new path-integral theory, we study the angle resolved photoemission spectra (ARPES) of one- and two-dimensional metallic many-electron systems coupled with Einstein phonons. The multiple scatterings of electrons due to phonons are shown to completely dominate the ARPES, even if the electron-phonon coupling strength is intermediate. These multiple scatterings result in spectral evolution from a broad Gaussian to a two-headed asymmetric Lorentzian as the spectrum moves from the band bottom to the Fermi surface (EF). We have also found that this two-headed structure near EF becomes most distinct in the two dimensional non-half-filled cases with no charge density wave gap. These results qualitatively agree with the experiments of ARPES on the Be(0001) surface and Bi2Sr2CaCu2O8.