Recently, the team of Professor Wu Jinsong and Professor Tang Xinfeng from the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing at Wuhan University of Technology made significant progress in the field of low-bandgap semiconductors. Their study, titled “Current Induced Electromechanical Strain in Thin Antipolar Ag₂Se Semiconductor”, was published in the prestigious international academic journal Nature Communications. The State Key Laboratory of Materials Composite and New Technology is the first affiliated institution, with Professors Wu Jinsong and Zhang Shujun from the University of Wollongong, Australia, serving as co-corresponding authors. Dr. Luo Hao and Liang Qi are the co-first authors.

Currently, research on electromechanical coupling in various material systems is attracting considerable attention. However, the electromechanical coupling mechanisms in low-bandgap semiconductors remain unclear. In nanoscale actuators application, materials are required to generate substantial elastic strain under an applied electric field. In certain specific cases, electromechanical actuators must also possess ideal electrical conductivity. Given these requirements, there is an urgent need to explore electromechanical coupling mechanisms in low-bandgap semiconductors that can fulfill these demands.

Against this backdrop, the study employed advanced techniques such as in situ transmission electron microscopy (TEM) to deeply investigate the antipolar Ag₂Se semiconductor. The research revealed that an electric current could induce significant electromechanical strain in thin Ag₂Se films. In situ TEM observations showed that when the applied voltage increased from 0V to 0.5V (corresponding to a current density of approximately 2.15×10⁹ A/m²), the Ag₂Se sample exhibited a strain of approximately 6.7%. The high-resolution imaging capabilities of in situ TEM enabled the clear visualization of the microstructural evolution and phase transition process in Ag₂Se under the influence of the electric current. Using selected area electron diffraction (SAED) techniques, the orientation of the thin film and the occurrence of phase transitions were precisely determined, providing key evidence for understanding the mechanism behind the electromechanical strain generation.

This study not only reveals a novel mechanism of current-induced electromechanical strain in the low-bandgap semiconductor Ag₂Se, but also provides a solid theoretical foundation and practical guidance for its widespread application in electromechanical coupling devices and related fields. These findings are expected to drive technological innovations in these areas.

Figure 1 In situ electron microscopy observation of electromechanical strain in Ag₂Se thin films

Figure 2 Spontaneous polarization and antiparallel polarization of α-Ag₂Se

Figure 3 Current-induced dipole reconstruction and lattice strain

Figure 4 α→β phase transition interface and strain mechanism

Hao Luo, Qi Liang, Anan Guo, Yimeng Yu, Haoyang Peng, Xiaoyi Gao, Yihao Hu, Xianli Su, Ctirad Uher, Yu Zheng, Dongwang Yang, Xiaolin Wang, Qingjie Zhang, Xinfeng Tang, Shi Liu, Gustaaf Van Tendeloo, Shujun Zhang* and Jinsong Wu*. Current induced electromechanical strain in thin antipolar Ag2Se semiconductor. Nature Communication,  2025, 16, 1818.

Paper link：https://doi.org/10.1038/s41467-025-57057-5

Written by: Wu Jinsong, Huang Linglin

Rewritten by: Liang Muwei

Edited by: Wang Jingjing, Li Tiantian, Li Huihui

Source: Institute of New Materials（State Key Laboratory of Advanced Technology For Materials Synthesis and Processing）