Theoretical description of thermal transport in graphene: The issues of phonon cut‐off frequencies and polarization branches

Abstract

AbstractWe discuss theoretical approaches for description of the phonon thermal transport in graphene and identify open questions and problems. Specifically, we show that due to a fundamental ambiguity in the definition of the intrinsic thermal conductivity of two‐dimensional (2‐D) systems the calculations that use an arbitrary low‐bound cut‐off for the phonon frequency in the thermal conductivity integral lead to erroneous results. The problem of the relative contributions of the longitudinal acoustic (LA), transverse acoustic (TA), and out‐of‐plane phonon polarization branches to thermal transport in graphene is also discussed. Theoretical thermal conductivity data for graphene, obtained by different approaches, are compared with those for carbon nanotubes.