Professor Yue Shengying from Xi'an Jiaotong University (XJTU), in collaboration with researchers from Peking University, has made significant advances in understanding the effects of inhomogeneous strain on thermal transport in nanomaterials. Nanomaterials exhibit excellent mechanical properties, enabling them to withstand high strain and thus alter their physical and chemical properties. This has led to the development of a number of advanced functional materials and devices, such as high-mobility chips, highly sensitive photodetectors, high-temperature superconductors, high-performance solar cells, and electrocatalysts.

Despite extensive research on strain-engineered electronic transport and band structure, the mechanisms of thermal transport under inhomogeneous strain remain underexplored due to challenges in isolating strain effects from other factors and combining nanoscale thermal transport measurements with atomic-scale phonon spectroscopy.

To address this, Professor Yue Shengying from Xi'an Jiaotong University, along with researchers from Peking University, proposed a new experimental strategy. They induced inhomogeneous strain fields by bending single silicon nanoribbons (SiNRs) on a custom-built suspended microdevice and characterized the local lattice vibration spectrum using scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) with sub-nanometer resolution. Their findings revealed that a strain gradient of 0.112 percent/nm significantly reduces thermal conductivity by 34±5 percent, which is over three times the modulation effect observed under uniform strain in previous studies. This demonstrates a unique phonon spectrum broadening effect and an anomalous suppression of thermal transport caused by strain gradients.

The work, titled "Suppressed thermal transport in silicon nanoribbons by inhomogeneous strain", was published in Nature. Researcher Yang Lin and Professor Yue are the primary authors.