Thermal Transport in SiBN ceramics: Density Functional Theory Calculations and Molecular Dynamics Simulations

Reference Presenter Authors
(Institution)
Abstract
14-071 Peter Kroll Kroll, P.(UT Arlington); We study thermal conductivity of amorphous silicon boron nitride (a-SiBN) for different compositions and densities as a function of temperature using density functional theory (DFT) calculations and equilibrium molecular dynamic (MD) simulations. Our library of amorphous structures consists of small network models comprising 100 – 200 atoms and large-scale models with up to 57000 atoms. We use two distinct approaches to compute thermal conductivity of a-SiBN: Clarke’s phenomenological model with elasticity data obtained by DFT calculations and the Green Kubo method applied to equilibrium MD simulations. Both approaches provideconsistent results at high temperatures. Thermal conductivity of a-SiBN depends on composition and increases as the BN content in the structure increases. The effect is pronounced at low temperature but almost vanishes at high temperature. Furthermore, thermal conductivity depends on density and porosity, with a linear relation between ? and density.
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