AI 中文总结
研究揭示菱面石墨烯中存在受小扭转角调控的拓扑跨莫尔轨道，解释了分数量子反常霍尔效应的微观机制，为合成拓扑量子计算平台提供了新途径。
AI 中文摘要
分数量子反常霍尔效应（FQAHE）是分形陈绝缘体表现出的物理现象，近期已在扭曲MoTe₂和菱面石墨烯/hBN莫尔超晶格中得到验证，为拓扑量子计算开辟了新途径。实现这一前景的核心是理解其微观机制，但菱面石墨烯的该机制仍不明确，关键在于其两个看似矛盾的条件：存在明显的小扭转角（θ）莫尔界面，且电子需远离该界面。本研究通过满足上述两个条件的扫描隧道显微镜成像，捕捉到菱面六方层石墨烯中发生的剧烈电子结构重塑，这种重塑由未被预料的“跨莫尔轨道”引起——该轨道出现在莫尔界面另一侧的远处，但在所有测量填充率下均维持莫尔周期性。我们可视化了一系列空间和能量上不同的跨莫尔轨道，电子需按顺序填充这些轨道：预期在小填充率下负责FQAHE的最低能量轨道呈空笼状。值得注意的是，当θ≥1°时，这些跨莫尔轨道消失，类似器件中的QAHE平台也随之消失。模拟显示，相互作用驱动的电荷再分布机制塑造了跨莫尔轨道及对应的陈迷你带。本研究的发现提供了缺失的微观联系，自然解释了矛盾的条件：电子并非简单地远离小θ莫尔界面，而是被强制进入在此条件下形成的拓扑跨莫尔轨道。我们的微观诊断技术解锁了大量潜在的“合成”FQAHE平台。
英文摘要
The fractional quantum anomalous Hall effect (FQAHE) exhibited in fractional Chern insulators has recently been demonstrated in twisted MoTe2 and rhombohedral graphene/hBN moiré superlattices, promising new routes toward topological quantum computation. Central to realizing this promise is the understanding of the underlying microscopic mechanism. This, however, remains elusive in the case of rhombohedral graphene, with the crux being its two seemingly paradoxical conditions: a pronounced small-twist-angle (θ) moiré interface, yet only when electrons are kept distant from it. Here, by scanning tunnelling microscopic imaging with both conditions fulfilled, we capture dramatic electronic structure reshaping in rhombohedral hexalayer graphene by unforeseen 'trans-moiré orbitals', which emerge on the other, distant side of the moiré interface but nevertheless enforce the moiré periodicity at all measured fillings. We visualize a hierarchy of spatially and energetically distinct trans-moiré orbitals which doped electrons must sequentially occupy--the lowest-energy orbital, expectedly responsible for the FQAHE at small fillings, carries a hollow-cage-like shape. Remarkably, these trans-moiré orbitals vanish at θ {\gtrsim} 1°, and so do QAHE plateaus in similar devices. Simulations reveal an interaction-driven charge-redistribution mechanism which shapes the trans-moiré orbitals and corresponding Chern minibands. With our findings providing the missing microscopic link, the paradoxical conditions find a natural explanation: electrons are not simply kept distant from a small-θ moiré interface; they are forced into topological trans-moiré orbitals, forged precisely under such conditions. Our microscopic diagnostics unlocks a wide range of possible 'synthetic' FQAHE platforms.
