Theory of remote phonon scattering in top-gated single-layer graphene

Abstract

We extend the theory of interfacial plasmon-phonon scattering to top-gated single-layer graphene. As with bottom-gated graphene, interfacial plasmon-phonon (IPP) modes are formed from the coupling between the graphene plasmon and the surface polar phonon modes in the top and bottom oxides. We study the effect of the top oxide thickness on dynamic screening and electron-IPP coupling. The remote phonon-limited electron mobility ${\ensuremath{\mu}}_{\mathrm{RP}}$ and electron scattering rates in a HfO${}_{2}$-covered, SiO${}_{2}$-supported single-layer graphene are computed at various electron densities $n$ for different dielectric thickness ${t}_{\mathrm{ox}}$. We find that ${\ensuremath{\mu}}_{\mathrm{RP}}$ is much more dependent on ${t}_{\mathrm{ox}}$ at low $n$. They also agree with the experimentally estimated room temperature ${\ensuremath{\mu}}_{\mathrm{RP}}$ from Zou et al. [Phys. Rev. Lett. 105, 126601 (2010)]. The electron density dependent ${\ensuremath{\mu}}_{\mathrm{RP}}$ is predicted to be between 5500 and $24\phantom{\rule{0.16em}{0ex}}200$ cm${}^{2}$V${}^{\ensuremath{-}1}$s${}^{\ensuremath{-}1}$ from $n={10}^{12}$ to ${10}^{13}$ cm${}^{\ensuremath{-}2}$ at 300 K.