Pressure induced semimetal-to-metal transition and new structure of Ta2NiSe5 above 10 GPa

作     者：Gan, Xiaolong Zhang, Han Jin, Shuoxue Chen, Dongliang Guo, Zhiying 

作者机构：Chinese Acad Sci Inst High Energy Phys Beijing Synchrotron Radiat Facil Beijing 100049 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China 

出 版 物：《JOURNAL OF PHYSICS-CONDENSED MATTER》 (J Phys Condens Matter)

年 卷 期：2025年第37卷第12期

页      面：125401-125401页

核心收录：

学科分类：07[理学] 070203[理学-原子与分子物理] 0702[理学-物理学] 

基　　金：Key R&D Program of China [2023YFF0716100] National Key R&D Program of China 

主　　题：Ta2NiSe5 high-pressure semimetal-metal transition phase transformation mechanism 

摘      要：Previous studies of the transition metal chalcogenide Ta2NiSe5 has identified two phase transitions occurring between 0-10 GPa, involving the excitonic insulator-to-semiconductor transition at 1 GPa and the semiconductor-to-semimetal transition at 3 GPa. However, there is still a lack of in-depth research on the changes in its physical properties changes above 10 GPa. In this study, Ta2NiSe5 were investigated under high-pressure conditions using high-pressure x-ray diffraction and high-pressure x-ray absorption experiments. During the experimental process, a novel phase transition from the semimetal to the metal phase was observed between 10-60 GPa, specifically between 10-14 GPa, and the structure of the new phase was determined to be P2(1)/m through first-principles calculations. This transition mechanism is attributed to the sliding of the weakly coupled layers of Ta2NiSe5 within the a-c plane, leading to changes in the crystal lattice constants and symmetry. This research fills a gap in the understanding of Ta2NiSe5 s crystal structure under high pressure and contributes to the broader field of transition metal chalcogenides.