发表机构
Department of Physics, University of Washington; Department of Materials Science and Engineering, University of Washington; Research Center for Electronic and Optical Materials, National Institute for Materials Science; Research Center for Materials Nanoarchitectonics, National Institute for Materials Science（华盛顿大学物理系; 华盛顿大学材料科学与工程系; 物质材料研究机构电子与光学材料研究中心; 物质材料研究机构的材料纳米结构研究中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
扭曲Bernal双层-三层石墨烯中实现起始超导与可调Chern绝缘体，通过位移场调控，超导口袋在绝缘边界附近形成，且拓扑可调。
AI 中文摘要
由扭曲Bernal和菱面体多层石墨烯组装而成的莫尔超晶格承载着丰富的相互作用驱动的磁性和拓扑态，然而在这些系统中，除了邻近过渡金属二硫化物的情况外，尚未观察到超导现象。在此，我们报告了由六方氮化硼封装的扭曲Bernal双层-三层石墨烯中的起始超导和可调Chern绝缘体。在从θ = 1.05°到1.50°的扭曲角范围内，对于电子掺杂，Chern绝缘体在整数和分数莫尔填充下形成，其Chern数高达|C| = 3，由扭曲角设定并通过掺杂调节。在θ = 1.18°时，对于空穴掺杂，形成对称性破缺的金属区域，并在能带填充ν = -2处承载一个平凡绝缘体。仅位移场即可将该绝缘体驱动到具有尖锐转变、明确临界电流和临界温度的起始超导口袋中，该临界温度在绝缘边界附近达到峰值，尽管电阻并未降至零。面内磁场扩展了该口袋，其持续超过弱耦合Pauli极限的四倍以上，并稳定了第二个口袋，其中临界电流的类Fraunhofer调制标志着相位相干配对。因此，扭曲Bernal双层-三层石墨烯提供了一个单一栅极可调系统，在该系统中，配对可与Chern绝缘体相互连接，而后者的拓扑本身就是一个可调参数。
英文摘要
Moiré superlattices assembled by twisting Bernal and rhombohedral multilayer graphene host a rich set of interaction-driven magnetic and topological states, yet superconductivity has not been observed in these systems except in proximity to a transition-metal dichalcogenide. Here we report incipient superconductivity and tunable Chern insulators in twisted bilayer-trilayer graphene encapsulated by hexagonal boron nitride. Across twist angles from $θ= 1.05^\circ$ to $1.50^\circ$, Chern insulators form at integer and fractional moiré fillings for electron doping, with Chern numbers up to |C| = 3 set by twist angle and tuned by doping. At $θ= 1.18^\circ$, a symmetry-broken metallic region forms for hole doping and hosts a trivial insulator at band filling $ν= -2$. Displacement field alone drives this insulator into a pocket of incipient superconductivity with a sharp transition, a well-defined critical current, and a critical temperature that peaks near the insulating boundary, although the resistance does not fall to zero. In-plane magnetic field expands the pocket, which persists to more than four times the weak-coupling Pauli limit, and stabilizes a second pocket in which Fraunhofer-like modulation of the critical current signals phase-coherent pairing. Twisted bilayer-trilayer graphene thus offers a single gate-tunable system in which pairing can be interfaced with Chern insulators whose topology is itself an adjustable parameter.
Comments23 pages, 23 figures, 1 table
