Pressure-driven symmetry breaking and electron disproportionation of the trigonal Nb_(3)cluster in Nb_(3)Cl_(8)  

作　　者：Zimin Jiang Dequan Jiang Yiming Wang Chen Li Ke Liu Ting Wen Fuyang Liu Zhengyang Zhou Yonggang Wang 

机构地区：[1]Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing 100094,China [2]Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 201899,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2022年第7期153-158,共6页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.52073003);the Major Program of National Natural Science Foundation of China(Grant No.22090041);the National Key R&D Program of China(Grant No.2018YFA0305900);the Shanghai Sailing Program(Grant No.21YF1454400)。

摘　　要：Symmetry breaking of metal cluster-based strongly correlated systems can give rise to collective phenomena.Here,the twodimensional Nb_(3) cluster compound Nb_(3)Cl_(8) is shown to suffer dramatic symmetry breaking and electron disproportionation under compression.A structural phase transition from trigonal P–3m1 to monoclinic C2/m is observed near 8 GPa with the three-fold symmetry breaking.Electron disproportionation occurs on Nb_(3) clusters from delocalized Nb^(8/3+)Nb^(8/3+)Nb^(8/3+)to localized Nb^(3+)Nb^(3+)Nb^(2+),which results in a subtle bandgap discontinuity,as evidenced by electrical transport and UV-Vis absorption measurements.

关 键 词：Nb_(3)Cl_(8) symmetry breaking electron disproportionation layered semiconductor high pressure 

分 类 号：O469[理学—凝聚态物理] O641.1[理学—电子物理学]