Room-temperature ballistic transport in narrow graphene strips

Abstract

We investigate electron-phonon couplings, scattering rates, and mean free paths in zigzag-edge graphene strips with widths of the order of $10\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Our calculations for these graphene nanostrips show both the expected similarity with single-wall carbon nanotubes (SWNTs) and the suppression of the electron-phonon scattering due to a Dirichlet boundary condition that prohibits one major backscattering channel present in SWNTs. Low-energy acoustic phonon scattering is exponentially small at room temperature due to the large phonon wave vector required for backscattering. We find within our model that the electron-phonon mean free path is proportional to the width of the nanostrip and is approximately $70\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ for an $11\text{\ensuremath{-}}\mathrm{nm}$-wide nanostrip.