Deep Strain-Mediated Thermal Transport in Silicon Nanowires

The ability to tune thermal transport through strain engineering offers transformative potential for advanced nanodevices, yet the impact of deep elastic strains (>5%) remains largely unexplored due to challenges in experimental implementation. Here we address this gap by developing a MEMS-based platform to probe strain-thermal transport coupling in suspended silicon nanowires. Through applying uniaxial tensile strains up to 5.65%, we observed three distinct regimes: thermal conductivity remains stable below 1% strain, shows slight enhancement before ∼3% strain, then undergoes a dramatic 55% suppression at 5.65% strain, the largest reversible modulation reported in silicon nanostructures. First-principles calculations reveal that the complex interplay between strain-induced phonon group velocity enhancement, scattering rates, and phonon-phonon interactions modulation is the main contributing factor to the nonmonotonic behaviors. This work establishes deep elastic strain as a powerful knob for dynamically controlling thermal transport, with immediate implications for adaptive thermal management in nanoelectronics and high-efficiency thermoelectrics.