Phys. Rev. B 110, 115107 (2024)
Yanyan Geng#, Jianfeng Guo#, Fanyu Meng#, Manyu Wang, Shuo Mi, Li Huang, Rui Xu, Fei Pang, Kai Liu, Shancai Wang, Hong-Jun Gao, Weichang Zhou, Wei Ji*, Hechang Lei*, and Zhihai Cheng*
Abstract:
Many intriguing quantum states of matter, such as unconventional superconductivity, magnetic phases, and fractional quantum Hall physics, emerge from the spatially correlated localized electrons in the flat bands of solid materials. By using scanning tunneling microscopy and spectroscopy (STM/STS), we report on the real-space investigation of correlated electrons in the flat band of superlattice 4𝐻𝑏−TaSe𝑥S2−𝑥. In contrast with the pristine 4𝐻𝑏−TaS2, the selenium (Se) substitutions significantly affect the interfacial transfer of correlated electrons between the charge density wave (CDW) states of 1𝑇- and 1𝐻−TaS2 layers and contribute the real-space fractional electron-filling configurations with the distributed electron-filled and void Star of David (SoD) clusters of the 1𝑇 layer. The site-specific STS spectra directly reveal their respective prominent spectra weight above 𝐸F and symmetric Mott-like spectra. In addition, the spatial distributions of these electron-filled SoDs in the 1𝑇 layer of 4𝐻𝑏−TaSe0.7S1.3 demonstrate different local short-range order, clearly indicating the complex neighboring interactions among the localized electrons in the flat band of the 1𝑇 layer. Our results not only provide in-depth insight into correlated electrons in the flat CDW band but also provide a simple platform to manipulate the electron-correlation-related quantum states.
DOI: 10.1103/PhysRevB.110.115107
Online Preview:
