论文标题

超导魔术角石墨烯中的非态性和竞争订单

Nematicity and Competing Orders in Superconducting Magic-Angle Graphene

论文作者

Cao, Yuan, Rodan-Legrain, Daniel, Park, Jeong Min, Yuan, Fanqi Noah, Watanabe, Kenji, Taniguchi, Takashi, Fernandes, Rafael M., Fu, Liang, Jarillo-Herrero, Pablo

论文摘要

固态系统中的强烈相互作用的电子通常表现出倾向于基态下多个断裂对称性的趋势。不同顺序参数之间的复杂相互作用会产生丰富的相图。在这里,我们报告了在魔法扭曲的双层石墨烯(TBG)中识别与旋转对称性断裂的相互交织相的鉴定。使用横向电阻测量值,我们发现了一个强烈的各向异性相,位于超导穹顶不足区域上方的“楔形”中。越过超导穹顶后,观察到临界温度的降低,类似于某些丘比特超导体的行为。此外,超导状态表现出对方向依赖性内磁场的各向异性反应,从而揭示了整个超导圆顶上的列神经配对状态。这些结果表明,列的波动可能在魔术角TBG的低温阶段中起重要作用,并为使用高度可调的Moiré超级晶格铺平了道路,以研究量子材料中的相互交织相。

Strongly interacting electrons in solid-state systems often display tendency towards multiple broken symmetries in the ground state. The complex interplay between different order parameters can give rise to a rich phase diagram. Here, we report on the identification of intertwined phases with broken rotational symmetry in magic-angle twisted bilayer graphene (TBG). Using transverse resistance measurements, we find a strongly anisotropic phase located in a 'wedge' above the underdoped region of the superconducting dome. Upon crossing the superconducting dome, a reduction of the critical temperature is observed, similar to the behavior of certain cuprate superconductors. Furthermore, the superconducting state exhibits a anisotropic response to an directional-dependent in-plane magnetic field, revealing a nematic pairing state across the entire superconducting dome. These results indicate that nematic fluctuations might play an important role in the low-temperature phases of magic-angle TBG, and pave the way for using highly-tunable moiré superlattices to investigate intertwined phases in quantum materials.

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