Diffusion thermopower, Sd, in suspended graphene is investigated for 100 < T< 350 K. Electrons are assumed to be
scattered by in-plane and out-of-plane acoustic phonons. Numerical results show that, temperature dependence of Sd, is
almost linear for both out-of-plane phonons and in-plane phonons, dominant contribution being from out-of-plane
phonons. Comparison with recent available experimental thermopower data [Xu et al arXiv: 1012. 2937v1, (condmat.
mes-hall)] obtains a good fit for T< 170K. Sd calculated using Mott expression is found to overestimate the values.
Carrier concentration dependence is also studied. Role and relative importance of the two scattering mechanisms is
studied.
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