摘要
The exertion of a long-period potential on two-dimensional(2D)systems leads to band-structure downfolding and the formation of mini flat bands,thereby providing a route for band engineering and enabling the realization of new physical phenomena through the tuning of electron–electron interactions.In this work,the effect of the moiré superlattice formed between the substrate and the bottom quintuple layer(QL)of 3-and 4-QL three-dimensional(3D)topological insulator Sb_(2)Te_(3) thin films on the top surface states is investigated.The scanning tunneling spectra reveal that the bulk-like bands exhibit potential variations consistent with the moirépattern.In contrast,the surface states display only minimal potential variations,resulting in the absence of mini-band formation in the top surface states.These surface states remain nearly unaffected,as confirmed by Landau-level spectroscopy and simulations.The results suggest distinct roles of the bottom-surface moirépotential on the bulk states and the top surface states in the weak coupling regime between the two surfaces.
基金
the supporting from the National Key R&D Program of China(Grant No.2022YFA1403102)
the National Natural Science Foundation of China(Grant Nos.12474478,92065102,and 12574094)。
