Enhanced phonon scattering in staggered-pore silicon metamaterials: A non-equilibrium molecular dynamics study

Abstract

Porous silicon nanostructures are promising candidates for thermal management applications, but the relationship between pore architecture and thermal transport remains incompletely understood. Here we use non-equilibrium molecular dynamics (NEMD) simulations with the Müller-Plathe method and the Stillinger–Weber potential to investigate how a staggered zigzag pore-wall architecture influences phonon heat transport in silicon at 300 K. Three structures are compared at matched system size: bulk silicon (φ = 0%), a single-pore geometry (φ = 6.84%), and a staggered zigzag configuration with two offset cubic pores (φ = 28.27%). A size-scaling study on bulk silicon confirms that the simulations operate in the ballistic transport regime and extrapolate to the experimental bulk thermal conductivity of 148 W/(m·K). At the matched comparison size of 26.1 nm, the porous structures achieve thermal conductivity reductions of 37% and 78% relative to bulk silicon. The porosity dependence follows a power law κ = κ 0 (1 − φ) n with n ≈ 4.70, exceeding the effective medium theory exponent (n = 1.5) by a factor of 3.1. These findings demonstrate that pore architecture can be a more effective design lever than porosity fraction alone for thermal conductivity reduction.