Lei Le, Dai Jiaqi, Dong Haoyu, Geng Yanyan, Cao Feiyue, Wang Cong, Xu Rui, Pang Fei, Liu Zheng-Xin, Li Fangsen, Cheng Zhihai, Wang Guang, Ji Wei
Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China.
Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China.
Nat Commun. 2023 Oct 9;14(1):6320. doi: 10.1038/s41467-023-42044-5.
Polymorphic structures of transition metal dichalcogenides (TMDs) host exotic electronic states, like charge density wave and superconductivity. However, the number of these structures is limited by crystal symmetries, which poses a challenge to achieving tailored lattices and properties both theoretically and experimentally. Here, we report a coloring-triangle (CT) latticed MoTe monolayer, termed CT-MoTe, constructed by controllably introducing uniform and ordered mirror-twin-boundaries into a pristine monolayer via molecular beam epitaxy. Low-temperature scanning tunneling microscopy and spectroscopy (STM/STS) together with theoretical calculations reveal that the monolayer has an electronic Janus lattice, i.e., an energy-dependent atomic-lattice and a Te pseudo-sublattice, and shares the identical geometry with the MoTe layer. Dirac-like and flat electronic bands inherently existing in the CT lattice are identified by two broad and two prominent peaks in STS spectra, respectively, and verified with density-functional-theory calculations. Two types of intrinsic domain boundaries were observed, one of which maintains the electronic-Janus-lattice feature, implying potential applications as an energy-tunable electron-tunneling barrier in future functional devices.
过渡金属二硫属化物（TMDs）的多晶结构包含奇异的电子态，如电荷密度波和超导性。然而，这些结构的数量受到晶体对称性的限制，这在理论和实验上都对实现定制晶格和性质构成了挑战。在此，我们报道了一种着色三角形（CT）晶格的单层MoTe，称为CT-MoTe，它是通过分子束外延将均匀且有序的镜面对称孪晶界可控地引入原始单层中构建而成的。低温扫描隧道显微镜和光谱（STM/STS）以及理论计算表明，该单层具有电子雅努斯晶格，即能量依赖的原子晶格和Te赝子晶格，并且与MoTe层具有相同的几何结构。CT晶格中固有的类狄拉克和平坦电子能带分别由STS光谱中的两个宽峰和两个突出峰识别，并通过密度泛函理论计算得到验证。观察到两种类型的本征畴界，其中一种保持了电子雅努斯晶格特征，这意味着其在未来功能器件中作为能量可调电子隧穿势垒具有潜在应用。
