Observation of multiple charge density wave phases in epitaxial monolayer 1T-VSe_(2) film  

作　　者：Junyu Zong Yang Xie Qinghao Meng Qichao Tian Wang Chen Xuedong Xie Shaoen Jin Yongheng Zhang Li Wang Wei Ren Jian Shen Aixi Chen Pengdong Wang Fang-Sen Li Zhaoyang Dong Can Wang Jian-Xin Li Yi Zhang 宗君宇;谢阳;孟庆豪;田启超;陈望;谢学栋;靳少恩;张永衡;王利;任伟;沈健;陈爱喜;王鹏栋;李坊森;董召阳;王灿;李建新;张翼(National Laboratory of Solid State Microstructure,School of Physics,Nanjing University,Nanjing 210093,China;Vacuum Interconnected Nanotech Workstation(Nano-X),Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO),Chinese Academy of Sciences,Suzhou 215123,China;Department of Applied Physics,Nanjing University of Science and Technology,Nanjing 210094,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)

机构地区：[1]National Laboratory of Solid State Microstructure,School of Physics,Nanjing University,Nanjing 210093,China [2]Vacuum Interconnected Nanotech Workstation(Nano-X),Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO),Chinese Academy of Sciences,Suzhou 215123,China [3]Department of Applied Physics,Nanjing University of Science and Technology,Nanjing 210094,China [4]Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China

出　　处：《Chinese Physics B》2022年第10期137-145,共9页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos. 92165205, 11790311, 12004172, 11774152, 11604366, and 11634007);the National Key Research and Development Program of China (Grant Nos. 2018YFA0306800 and 2016YFA0300401);the Program of High-Level Entrepreneurial and Innovative Talents Introduction of Jiangsu Province, the Jiangsu Planned Projects for Postdoctoral Research Funds (Grant No. 2020Z172);the Natural Science Foundation of Jiangsu Province, China (Grant No. BK 20160397)。

摘　　要：As a special order of electronic correlation induced by spatial modulation, the charge density wave(CDW) phenomena in condensed matters attract enormous research interests. Here, using scanning-tunneling microscopy in various temperatures, we discover a hidden incommensurate stripe-like CDW order besides the(■) CDW phase at low-temperature of 4 K in the epitaxial monolayer 1T-VSe_(2) film. Combining the variable-temperature angle-resolved photoemission spectroscopic(ARPES) measurements, we discover a two-step transition of an anisotropic CDW gap structure that consists of two parts △_(1) and△_(2). The gap part ?1 that closes around ~ 150 K is accompanied with the vanish of the(√7×√3) CDW phase. While another momentum-dependent gap part △_(2) can survive up to ~ 340 K, and is suggested to the result of the incommensurate CDW phase. This two-step transition with anisotropic gap opening and the resulted evolution in ARPES spectra are corroborated by our theoretical calculation based on a phenomenological form for the self-energy containing a two-gap structure △_(1) +△_(2), which suggests different forming mechanisms between the(√7×√3) and the incommensurate CDW phases. Our findings provide significant information and deep understandings on the CDW phases in monolayer 1T-VSe_(2) film as a two-dimensional(2D) material.

关 键 词：charge density waves VSe_(2) band structures STM ARPES 

分 类 号：O469[理学—凝聚态物理]