Snap-Through Thermomechanical Metamaterials for High-Performance Thermal Rectification

The work targets thermal diodes, which move heat more easily in one direction than the other, for thermal management and thermal logic. The authors propose a thermomechanical metamaterial that uses temperature-responsive actuation and structural bistability. The device combines shape memory alloy (SMA) springs with pre-buckled copper strips that snap through under thermal gradients. This snap-through reconfiguration is designed to enable contact-based conduction in the forward direction while suppressing reverse heat flow through radiative isolation. The authors develop a coupled analytical model and validate performance using finite element simulations and experiments. They report a thermal rectification ratio above 900, along with robust cycling stability and structural integrity, and they describe a modular stacking approach to improve scalability.