近日，美国加州理工学院Stevan Nadj-Perge团队研究了超导体中谷间间隙和多体共振的求解。该项研究成果发表在2026年2月4日出版的《自然》杂志上。

魔角扭曲多层石墨烯作为一种高度可调的莫尔材料体系，以其强电子关联效应与稳健的超导特性而备受关注。然而，理解低温超导相与前期关联母态之间的关系仍是当前挑战。

研究组利用扫描隧道显微镜（STM）及其谱学技术，追踪了魔角扭曲三层石墨烯（MATTG）中由动态关联、谷间相干性与超导性相互作用形成的关联相生成序列。研究组在超导掺杂范围内发现费米能级处存在两个清晰分离的能隙。虽然此前被认为与赝能隙相关的外层能隙在高温和强磁场下持续存在，但新揭示的内层能隙更为脆弱，这与先前输运实验观测结果一致。

同位置进行的安德烈夫反射谱学分析显示其变化趋势与内层能隙的掺杂行为紧密关联，而与外层能隙无关。此外，纳米尺度畴界处的谱学测量进一步印证了两个能隙的迥异特性：内层能隙在结构变化中保持稳定。通过将实验结果与包含动态关联效应的拓扑重费米子（THF）模型对比，研究组认为外层能隙可能源于谷对称性破缺引起的阿布里科索夫-苏尔-近藤共振分裂。这些研究结果揭示了扭曲多层石墨烯中关联相之间存在复杂而可解析的层级结构关系。

附：英文原文

Title: Resolving intervalley gaps and many-body resonances in moiré superconductors

Author: Kim, Hyunjin, Rai, Gautam, Crippa, Lorenzo, Clugru, Dumitru, Hu, Haoyu, Choi, Youngjoon, Kong, Lingyuan, Baum, Eli, Zhang, Yiran, Holleis, Ludwig, Watanabe, Kenji, Taniguchi, Takashi, Young, Andrea F., Bernevig, B. Andrei, Valent, Roser, Sangiovanni, Giorgio, Wehling, Tim, Nadj-Perge, Stevan

Issue&Volume: 2026-02-04

Abstract: Magic-angle twisted multilayer graphene stands out as a highly tunable class of moiré materials that exhibit strong electronic correlations and robust superconductivity1,2,3,4. However, understanding the relationships between the low-temperature superconducting phase and the preceding correlated parent states remains a challenge. Here we use scanning tunnelling microscopy (STM) and spectroscopy to track the formation sequence of correlated phases established by the interplay of dynamic correlations, intervalley coherence and superconductivity in magic-angle twisted trilayer graphene (MATTG). We discover the existence of two well-resolved gaps pinned at the Fermi level within the superconducting doping range. Although the outer gap, previously associated with the pseudogap phase5,6, persists at high temperatures and magnetic fields, the newly revealed inner gap is more fragile, in line with previous transport experiments1,2,4. Andreev reflection spectroscopy taken at the same location confirms a clear trend that closely follows the doping behaviour of the inner gap and not the outer one. Moreover, spectroscopy taken at nanoscale domain boundaries further corroborates the contrasting behaviour of the two gaps, with the inner gap remaining resilient to structural variations. By comparing our results with recent topological heavy fermion (THF) models that include dynamical correlations7,8, we find that the outer gap probably arises from a splitting of the Abrikosov–Suhl–Kondo resonance9,10 owing to the breaking of the valley symmetry. Our results indicate an intricate yet tractable hierarchy of correlated phases in twisted multilayer graphene.

DOI: 10.1038/s41586-025-10067-1

Source: https://www.nature.com/articles/s41586-025-10067-1