近日，上海交通大学王世勇团队研究了扭曲双层MoTe₂中的成像莫尔平带和维格纳分子晶体。2026年1月20日出版的《国家科学评论》杂志发表了这项成果。

转角双层二碲化钼（tMoTe₂）近来已成为实现强关联与拓扑量子相的重要平台。然而，其微观电子结构在很大程度上仍未得到探索。

研究组利用扫描隧道显微镜/谱技术，对扭转角度为2.3°–3.8°的双栅极tMoTe₂器件中的莫尔平带进行了直接成像。双栅极设计允许独立调节能带填充与位移场，从而实现精细的光谱扫描成像。研究组发现低能平带局域于MX与XM位点，并在零电场下形成拓扑蜂巢晶格。施加的电场会解除层间简并，驱动体系向具有平庸拓扑的两个解耦三角晶格转变。研究结果与第一性原理计算相符，揭示了K谷杂化是这一现象的微观起源。在强莫尔势作用下，研究组观测到在填充数νMX=3时形成Kagome晶格的维格纳分子晶体，这展现了tMoTe₂中拓扑性与关联效应的电场调控能力。

附：英文原文

Title: Imaging moiré flat bands and wigner molecular crystals in twisted bilayer MoTe2

Author: Liu, Yufeng, Gu, Yu, Bao, Ting, Mao, Ning, Jiang, Shudan, Liu, Liang, Guan, Dandan, Li, Yaoyi, Zheng, Hao, Liu, Canhua, Watanabe, Kenji, Taniguchi, Takashi, Duan, Wenhui, Jia, Jinfeng, Liu, Xiaoxue, Li, Can, Zhang, Yang, Li, Tingxin, Wang, Shiyong

Issue&Volume: 2026-01-20

Abstract: Twisted bilayer MoTe2 (tMoTe2) has recently emerged as an exceptional platform for realizing strongly correlated and topological quantum phases. Yet, its microscopic electronic structure remains largely unexplored. Here, we use scanning tunneling microscopy/spectroscopy (STM/STS) to directly image the moiré flat bands in dual-gated tMoTe2 devices with twist angles of 2.3°–3.8°. A dual-gate design allows independent tuning of band filling and displacement field, enabling detailed spectroscopic mapping. We find that the low-energy flat bands are localized at MX and XM sites and form a topological honeycomb lattice at zero electric field. An applied electric field lifts the layer degeneracy, driving a transition to two decoupled triangular lattices with trivial topology. Our results match first-principles calculations, revealing K-valley hybridization as the microscopic origin. At large moiré potential, we observe Wigner molecular crystals forming a Kagome lattice at filling νMX = 3, demonstrating electric-field control of topology and correlation in tMoTe2.

DOI: 10.1093/nsr/nwag014

Source: https://dx.doi.org/10.1093/nsr/nwag014