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

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 = κ0(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.