Xia Yiyu, Han Zhongdong, Watanabe Kenji, Taniguchi Takashi, Shan Jie, Mak Kin Fai
School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, USA.
Nature. 2025 Jan;637(8047):833-838. doi: 10.1038/s41586-024-08116-2. Epub 2024 Oct 30.
Moiré materials have enabled the realization of flat electron bands and quantum phases that are driven by the strong correlations associated with flat bands. Superconductivity has been observed, but only in graphene moiré materials. The absence of robust superconductivity in moiré materials beyond graphene, such as semiconductor moiré materials, has remained a mystery and challenged our current understanding of superconductivity in flat bands. Here we report the observation of robust superconductivity in both 3.5° and 3.65° twisted bilayer tungsten diselenide (WSe), which hosts a hexagonal moiré lattice. Superconductivity emerges near half-band filling and zero external displacement fields. The optimal superconducting transition temperature is about 200 mK in both cases and constitutes about 1-2% of the effective Fermi temperature; the latter is comparable to the value in high-temperature cuprate superconductors and suggests strong pairing. The superconductor borders on two distinct metals below and above half-band filling; it undergoes a continuous transition to a correlated insulator by tuning the external displacement field. The observed superconductivity on the verge of Coulomb-induced charge localization suggests roots in strong electron correlations.
莫尔材料能够实现由与平带相关的强关联驱动的平电子带和量子相。已经观察到超导现象，但仅在石墨烯莫尔材料中。在除石墨烯之外的莫尔材料（如半导体莫尔材料）中缺乏稳健的超导性，这仍然是一个谜，并挑战了我们目前对平带中超导性的理解。在此，我们报告了在具有六边形莫尔晶格的3.5°和3.65°扭曲双层二硒化钨（WSe）中观察到稳健的超导性。超导性在接近半带填充和零外位移场时出现。在这两种情况下，最佳超导转变温度约为200 mK，约占有效费米温度的1-2%；后者与高温铜酸盐超导体中的值相当，表明存在强配对。超导体在半带填充以下和以上与两种不同的金属相邻；通过调节外位移场，它会连续转变为相关绝缘体。在库仑诱导电荷局域化边缘观察到的超导性表明其根源在于强电子关联。
