近日，美国麻省理工学院巨龙团队研究了菱形石墨烯的手性超导特征。这一研究成果发表在2025年5月22日出版的《自然》杂志上。

手性超导体是非常规的超导态，自发地打破时间反转对称性，通常以非零角动量的库珀配对为特征。这些状态可能承载马约拉纳费米子，并为拓扑物理研究和容错量子计算提供重要平台。尽管对几个候选系统进行了深入的搜索和长期的研究，但到目前为止，手性超导性仍然难以捉摸。

研究组报告了在没有莫尔超晶格效应的情况下，在菱面体四层和五层石墨烯中发现了稳健的非常规超导性。他们在五个器件的栅极诱导平导带中观察到两个超导态，T_c高达300 mK，电荷密度n_e低至2.4*10¹¹ cm^-2。

研究组还发现了由于电子轨道运动引起的自发时间反转对称性破缺，一些观测表明了这些超导态的手性性质，包括：1）在超导状态下，R_xx在变化的平面外磁场B⊥中表现出磁滞，这是所有其他超导体所没有的；2）超导态对平面内磁场具有鲁棒性，并在自旋和谷极化的四分之一金属相中发展；3）正常状态在零磁场和磁滞下显示异常霍尔信号。

研究组还观察到临界B⊥为1.4特斯拉，高于任何石墨烯超导电性，表明在BCS-BEC交叉附近存在强耦合超导电性。该观察为拓扑超导的研究建立了一种纯碳材料，有望探索马约拉纳模式和拓扑量子计算。

附：英文原文

Title: Signatures of chiral superconductivity in rhombohedral graphene

Author: Han, Tonghang, Lu, Zhengguang, Hadjri, Zach, Shi, Lihan, Wu, Zhenghan, Xu, Wei, Yao, Yuxuan, Cotten, Armel A., Sedeh, Omid Sharifi, Weldeyesus, Henok, Yang, Jixiang, Seo, Junseok, Ye, Shenyong, Zhou, Muyang, Liu, Haoyang, Shi, Gang, Hua, Zhenqi, Watanabe, Kenji, Taniguchi, Takashi, Xiong, Peng, Zumbhl, Dominik M., Fu, Liang, Ju, Long

Issue&Volume: 2025-05-22

Abstract: Chiral superconductors are unconventional superconducting states that break time reversal symmetry spontaneously and typically feature Cooper pairing at non-zero angular momentum. Such states may host Majorana fermions and provide an important platform for topological physics research and fault-tolerant quantum computing1–7. Despite intensive search and prolonged studies of several candidate systems8–26, chiral superconductivity has remained elusive so far. Here we report the discovery of robust unconventional superconductivity in rhombohedral tetra- and penta-layer graphene without moiré superlattice effects. We observed two superconducting states in the gate-induced flat conduction bands with Tc up to 300 mK and charge density ne down to 2.4*1011 cm-2 in five devices. Spontaneous time-reversal-symmetry-breaking due to electron’s orbital motion is found, and several observations indicate the chiral nature of these superconducting states, including: 1. In the superconducting state, Rxx shows magnetic hysteresis in varying out-of-plane magnetic field B⊥—absent from all other superconductors; 2. the superconducting states are robust against in-plane magnetic field and are developed within a spin- and valley-polarized quarter-metal phase; 3. the normal states show anomalous Hall signals at zero magnetic field and magnetic hysteresis. We also observed a critical B⊥ of 1.4 Tesla, higher than any graphene superconductivity and indicates a strong-coupling superconductivity close to the BCS-BEC crossover27. Our observations establish a pure carbon material for the study of topological superconductivity, with the promise to explore Majorana modes and topological quantum computing.

DOI: 10.1038/s41586-025-09169-7

Source: https://www.nature.com/articles/s41586-025-09169-7