Zhao Wei-Min, Ding Wenjun, Wang Qi-Wei, Meng Yu-Xin, Zhu Li, Jia Zhen-Yu, Zhu Wenguang, Li Shao-Chun
National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.
International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale, Department of Physics, University of Science and Technology of China, Hefei 230026, China.
Phys Rev Lett. 2023 Aug 25;131(8):086501. doi: 10.1103/PhysRevLett.131.086501.
Strong electron correlation under two-dimensional limit is intensely studied in the transition metal dichalcogenides monolayers, mostly within their charge density wave (CDW) states that host a star of David period. Here, by using scanning tunneling microscopy and spectroscopy and density functional theory calculations with on-site Hubbard corrections, we study the VTe_{2} monolayer with a different 2sqrt[3]×2sqrt[3] CDW period. We find that the dimerization of neighboring Te-Te and V-V atoms occurs during the CDW transition, and that the strong correlation effect opens a Mott-like full gap at Fermi energy (E_{F}). We further demonstrate that such a Mott phenomenon is ascribed to the combination of the CDW transition and on-site Coulomb interactions. Our work provides a new platform for exploring Mott physics in 2D materials.
二维极限下的强电子关联在过渡金属二硫属化物单层中受到广泛研究,主要是在其具有大卫之星周期的电荷密度波(CDW)态范围内。在此,我们通过扫描隧道显微镜和光谱以及带有在位哈伯德修正的密度泛函理论计算,研究了具有不同2√3×2√3 CDW周期的VTe₂单层。我们发现,在CDW转变过程中相邻的Te-Te和V-V原子发生二聚化,并且强关联效应在费米能(Eₚ)处打开了一个类似莫特的完全能隙。我们进一步证明,这种莫特现象归因于CDW转变和在位库仑相互作用的结合。我们的工作为探索二维材料中的莫特物理提供了一个新平台。