Anharmonic properties from a generalized third-order<i>ab initio</i>approach: Theory and applications to graphite and graphene

Abstract

We have implemented a generic method, based on the 2n+1 theorem within\ndensity functional perturbation theory, to calculate the anharmonic scattering\ncoefficients among three phonons with arbitrary wavevectors. The method is used\nto study the phonon broadening in graphite and graphene mono- and bi-layer. The\nbroadening of the high-energy optical branches is highly nonuniform and\npresents a series of sudden steps and spikes. At finite temperature, the two\nlinearly dispersive acoustic branches TA and LA of graphene have nonzero\nbroadening for small wavevectors. The broadening in graphite and bi-layer\ngraphene is, overall, very similar to the graphene one, the most remarkable\nfeature being the broadening of the quasi acoustical ZO' branch. Finally, we\nstudy the intrinsic anharmonic contribution to the thermal conductivity of the\nthree systems, within the single mode relaxation time approximation. We find\nthe conductance to be in good agreement with experimental data for the\nout-of-plane direction but to underestimate it by a factor 2 in-plane.\n

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Affiliated Institutions

• Centre National de la Recherche Scientifique FR
• Sorbonne Université FR

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