Ultra-high thermal rectification in silicon prism-shaped nanostructure using NEMD simulations

Abstract Efficient thermal management has become a critical challenge for modern nanoelectronic and microelectronic devices as heat dissipation increasingly limits performance and reliability. Thermal rectification (TR), the directional dependence of heat flow, provides a promising strategy for regulating nanoscale energy transport and enabling thermal diodes, logic gates, and autonomous heat regulators. In this work, we employ non-equilibrium molecular dynamics simulations to investigate TR in silicon (Si) prism-shaped nanostructures with trapezoidal cross-sections characterized by the pitch angle θ . The simulations reveal that geometric asymmetry strongly influences phonon transport, leading to tunable rectification behavior across different system lengths and angles. We systematically analyze the dependence of the rectification ratio on the pitch angle, structure length, and applied temperature bias, uncovering conditions under which pronounced rectification and non-linear heat transport emerge. The optimized Tersoff potential was employed to capture anharmonic effects and phonon scattering with high fidelity. These results underscore geometry-driven phonon filtering as a controllable approach to achieve directional heat transport in Si nanostructures. Moreover, they extend previous insights on spontaneous heat currents and infinite TR—previously observed in asymmetric graphene systems—to technologically relevant Si platforms. The influence of key geometrical parameters—namely, pitch angle, length, and thickness—on the TR ratio was systematically investigated. Overall, this study provides atomistic design guidelines for Si-based thermal rectifiers and establishes prism-shaped nanostructures as viable candidates for next-generation thermal management and energy conversion technologies.