Drag of electrons in graphene by substrate surface polar phonons

Article

关键词: THERMOELECTRIC-POWER;    TEMPERATURE-DEPENDENCE;    EPITAXIAL GRAPHENE;    MONOLAYER GRAPHENE;    CARBON NANOTUBES;    THERMOPOWER;    SCATTERING;    TRANSPORT;    GRAPHITE;    LIFETIMES;   

DOI  :  10.1103/PhysRevB.94.125403

来源: SCIE

【 摘 要 】

It is known that electron scattering by surface polar phonons (SPPs) of the substrate reduces their mobility in supported graphene. However, there is no experimental evidence for the contribution of the drag of electrons by SPPs to thermoelectric phenomena in graphene: graphene thermopower exhibits good agreement with Mott's law, which means that the diffusion contribution to the thermopower is dominant in a wide range of carrier densities and temperatures. Here we develop a complete theory of drag of electrons in graphene by SPPs. By solving the Boltzmann transport equation for electrons scattered by SPPs we derive SPP-drag contribution to the thermopower in graphene. Compared to diffusion thermopower, obtained values appear to be one order of magnitude lower for various substrates. This can be explained by the low occupation number of the SPPs and short mean free path of such phonons stemming from their small group velocity. We conclude that experiments on thermopower in graphene can be treated within the framework of Mott's law.

【 授权许可】

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