Park Jeong Min, Cao Yuan, Xia Li-Qiao, Sun Shuwen, Watanabe Kenji, Taniguchi Takashi, Jarillo-Herrero Pablo
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
National Institute for Materials Science, Tsukuba, Japan.
Nat Mater. 2022 Aug;21(8):877-883. doi: 10.1038/s41563-022-01287-1. Epub 2022 Jul 7.
The discovery of correlated states and superconductivity in magic-angle twisted bilayer graphene (MATBG) established a new platform to explore interaction-driven and topological phenomena. However, despite multitudes of correlated phases observed in moiré systems, robust superconductivity appears the least common, found only in MATBG and more recently in magic-angle twisted trilayer graphene. Here we report the experimental realization of superconducting magic-angle twisted four-layer and five-layer graphene, hence establishing alternating twist magic-angle multilayer graphene as a robust family of moiré superconductors. This finding suggests that the flat bands shared by the members play a central role in the superconductivity. Our measurements in parallel magnetic fields, in particular the investigation of Pauli limit violation and spontaneous rotational symmetry breaking, reveal a clear distinction between the N = 2 and N > 2-layer structures, consistent with the difference between their orbital responses to magnetic fields. Our results expand the emergent family of moiré superconductors, providing new insight with potential implications for design of new superconducting materials platforms.
魔角扭曲双层石墨烯(MATBG)中关联态和超导性的发现,为探索相互作用驱动和拓扑现象建立了一个新平台。然而,尽管在莫尔系统中观察到了众多关联相,但稳健的超导性似乎是最不常见的,仅在MATBG中发现,最近在魔角扭曲三层石墨烯中也有发现。在此,我们报告了超导魔角扭曲四层和五层石墨烯的实验实现,从而将交替扭曲魔角多层石墨烯确立为一个稳健的莫尔超导体家族。这一发现表明,该家族成员共享的平带在超导性中起着核心作用。我们在平行磁场中的测量,特别是对泡利极限违反和自发旋转对称性破缺的研究,揭示了N = 2层和N > 2层结构之间的明显区别,这与它们对磁场的轨道响应差异一致。我们的结果扩展了新兴的莫尔超导体家族,为新型超导材料平台的设计提供了具有潜在意义的新见解。