近日，美国康奈尔大学的Kin Fai Mak&Jie Shan及其研究团队取得一项新进展。经过不懈努力，他们揭示了扭曲双分子层WSe₂的超导性。相关研究成果已于2024年10月30日在国际权威学术期刊《自然》上发表。

本文报道了在具有六角莫尔晶格的3.5°和3.65°扭曲双层二硒化钨（WSe₂）中，均观察到了稳健的超导性。超导性出现在半带填充和零外部位移场附近。在这两种情况下，最优超导转变温度约为200mK，占有效费米温度的1-2%；后者与高温铜氧化物超导体的值相当，表明配对作用强烈。

该超导体在半带填充以下的金属态和半带填充以上的金属态之间，通过调节外部位移场，它可以连续过渡到相关绝缘体态。观察到的这种处于库仑诱导电荷局域化边缘的超导性，表明其根源在于强电子关联性。

据悉，莫尔材料已经实现了平电子能带和由平带强相关性驱动的量子相。尽管已在石墨烯莫尔材料中观察到超导性，但在石墨烯之外的莫尔材料（如半导体莫尔材料）中却始终未见稳定的超导性，这仍是一个未解之谜，并挑战了我们对平带中超导性的现有理解。

附：英文原文

Title: Superconductivity in twisted bilayer WSe₂

Author: Xia, Yiyu, Han, Zhongdong, Watanabe, Kenji, Taniguchi, Takashi, Shan, Jie, Mak, Kin Fai

Issue&Volume: 2024-10-30

Abstract: 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 (WSe₂), which hosts a hexagonal moiré lattice. Superconductivity emerges near half-band filling and zero external displacement fields. The optimal superconducting transition temperature is about 200mK 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.

DOI: 10.1038/s41586-024-08116-2

Source: https://www.nature.com/articles/s41586-024-08116-2