ISSN Online: 2377-424X
ISBN Print: 978-1-56700-474-8
ISBN Online: 978-1-56700-473-1
International Heat Transfer Conference 16
NEGATIVE GAUSSIAN CURVATURE INDUCES SIGNIFICANT SUPPRESSION OF THERMAL CONDUCTIVITY IN CARBON CRYSTALS
Sinopsis
From a mathematic category of surface Gaussian curvature, carbon allotropes can be classified into three types: zero curvature, positive curvature and negative curvature. By performing Green−Kubo equilibrium molecular dynamics simulations, we elucidate that the surface curvature has significant impacts on the phonon vibration and thermal conductivity (κ) of carbon crystals. As curving from the zero curvature to the negative or positive curvature structures, κ is dramatically reduced by several orders of magnitude. More interestingly, we find κ of
negatively curved carbon crystals exhibits a monotonic dependence on curvature. Through phonon mode analysis, we reveal that the curvature induces remarkable phonon softening in the phonon dispersion, which results in the reduction of phonon group velocity and the flattening of phonon band structure. Furthermore, the curvature is also found to induce phonon mode hybridization, leading to the suppression of phonon relaxation time. Our study provides physical insights to thermal transport in curvature materials, and would be valuable
towards the modulation of phonon activities by the surface curvature.