Phonon drag thermopower in graphene in equipartition regime

¹ Ioffe Physical-Technical Institute of the Russian Academy of Sciences - 194021 St. Petersburg, Russia
² St. Petersburg Academic University - Nanotechnology Research and Education Centre of the Russian Academy of Sciences - 194021 St. Petersburg, Russia
³ St. Petersburg Chemical Pharmaceutical Academy - 197022 St. Petersburg, Russia

^(a) kon@mail.ioffe.ru

Received: 7 June 2013
Accepted: 10 July 2013

Abstract

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 the interaction with intrinsic acoustic phonons. The temperatures considered a range from liquid nitrogen to the room level. It has turned out that the contribution to the 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 the thermoelectromotive force deriving from 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.