In most semiconducting metal chalcogenides, a large deformation is usually accompanied by a phase transformation, while the deformation mechanism remains largely unexplored. Herein, a phase-transformation-induced deformation in Ag₂Se is investigated by in situ transmission electron microscopy, and a new ordered high-temperature phase (named as α ′-Ag₂Se) is identified. The SeSe bonds are folded when the Ag⁺-ion vacancies are ordered and become stretched when these vacancies are disordered. Such a stretch/fold of the SeSe bonds enables a fast and large deformation occurring during the phase transition. Meanwhile, the different SeSe bonding states in α-, α ′-, β-Ag₂Se phases lead to the formation of a large number of nanoslabs and the high concentration of dislocations at the interface, which flexibly accommodate the strain caused by the phase transformation. This study reveals the atomic mechanism of the deformation in Ag₂Se inorganic semiconductors during the phase transition, which also provides inspiration for understanding the phase transition process in other functional materials.

中文翻译：

---

热电 Ag2Se 半导体中相变引起的巨大变形

在大多数半导体金属硫属化物中，大变形通常伴随着相变，而变形机制在很大程度上仍未得到探索。在此，通过原位透射电子显微镜研究了Ag ₂ Se 中的相变诱导变形，并鉴定了一种新的有序高温相（命名为 α '-Ag ₂ Se）。当 Ag ⁺ - 离子空位有序时，Se  Se 键被折叠，当这些空位无序时变得拉伸。Se  Se 键的这种拉伸/折叠能够在相变期间发生快速和大的变形。同时，α-、α′-、β-Ag _{2 中}不同的Se  Se 键合状态Se 相导致大量纳米板的形成和界面处高浓度的位错，这可以灵活地适应相变引起的应变。该研究揭示了Ag ₂ Se无机半导体在相变过程中变形的原子机制，也为理解其他功能材料的相变过程提供了启示。