  This letter calculates the contribution of electron-phonon interaction to
thermoelectric effects in graphene. One considers the case of free standing
graphene taking into account interaction with intrinsic acoustic phonons. The
temperatures considered range from liquid nitrogen to the room level. It has
turned out that the contribution to thermoelectromotive force due to electron
drag by phonons is determined by the Fermi energy in the sample and phonon
relaxation time. The explicit temperature dependence of the contribution to
thermoelectromotive force deriving from by phonons is weak in contrast to that
due to diffusion, which is directly proportional to temperature. The dependence
obtained suggests that at the temperatures considered, a high carrier
concentration and for samples with a high thermal conductivity, the phonon drag
contribution can become dominant. Thus a theoretical limit has been established
for a possible increase of the thermoelectromotive force through electron drag
by the intrinsic phonons of graphene.
