Theoretical study of the thermal conductivity of silica glass–crystal composites

Abstract

The heat dissipation of silicate glasses draws much attention for various applications, and the desire for glasses with high thermal conductivity remains an unsolved challenge. The structural origin of thermal conductivity in glass remains not fully understood. The present study aims to elucidate the impact of embedding highly thermally conductive crystalline α‐quartz in a silica glass matrix. We consider both nano‐thread (NT) (1D) and nano‐plate (NP) (2D) structures and use molecular dynamics simulations to evaluate the role of its connectivity on thermal conductivity in the glass–crystal composite as a function of the volume fraction of the α‐quartz region. The directional dependence of thermal conductivity was also investigated to obtain percolation threshold behavior along the cross‐sectional directions, whereas the parallel circuit model of electricity can be used to account for the change of thermal conductivity along the longitudinal direction. Incorporation of α‐quartz NTs or NPs into silica glass offers the opportunity to enhance its thermal conductivity.