Realization of Reversible Regulation of Thermal Conductivity in 2D Materials through Engineered Acoustic Mismatch

In modern electronic devices, active control of heat transport is essential for performance and reliability, yet most existing approaches to thermal conductivity modulation are irreversible and fixed after synthesis. Here, we propose a reversible thermal conductivity regulation strategy based on engineered junctions in two-dimensional (2D) materials. By locally coupling the central region of a 2D heat-conducting layer to a substrate, we create a junction that exhibits distinct out-of-plane acoustic phonon (ZA mode) properties relative to the surrounding uncoupled region, thereby introducing an engineered acoustic mismatch to dynamically regulate heat transport. Using homogeneous nonequilibrium molecular dynamics (HNEMD) and nonequilibrium molecular dynamics (NEMD) simulations with a graphene/hexagonal boron nitride (Gr/h-BN) junction as a model system, we show that tuning the interlayer coupling in the junction region can suppress the thermal conductivity of graphene by up to a factor of 49 at 100 K. At room temperature (300 K), the modulation ratio can still reach 6.5. This effectiveness of this architecture is not limited by the type of substrates and heat-conducting layer, demonstrating excellent versatility and robustness. The proposed architecture offers a promising route toward dynamic, reversible thermal management in 2D materials.