Kumar Ravi, Haug André, Kim Jehyun, Yutushui Misha, Khudiakov Konstantin, Bhardwaj Vishal, Ilin Alexey, Watanabe K, Taniguchi T, Mross David F, Ronen Yuval
Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan.
Nat Commun. 2025 Aug 6;16(1):7255. doi: 10.1038/s41467-025-62650-9.
Even-denominator fractional quantum Hall states are promising candidates for fault-tolerant quantum computing due to their underlying non-Abelian topological order. However, the topological order of these states remains hotly debated. Here, we report transport measurements on ultra-clean bilayer graphene heterostructures, where we observed four quarter-filled states and their corresponding Levin-Halperin daughter states, constraining their topological order. Moreover, we complete the sequence of half-filled plateaus by detecting states at and whose daughters suggest an alternating sequence of non-Abelian orders. This pattern suggests a universal origin supporting their use in identifying topological order at even-denominator fillings, though further confirmation is needed via direct measurements. The observed quarter- and half-filled states appear in N = 0 and N = 1 Landau levels, respectively, and thus highlight a competition between interactions favoring paired states of either four- or two-flux composite fermions. Additionally, we observe several 'next-generation' quantum Hall states that require strong interactions between composite fermions.
由于其潜在的非阿贝尔拓扑序，偶数分母分数量子霍尔态是容错量子计算的有前途的候选者。然而，这些态的拓扑序仍然存在激烈的争论。在这里，我们报告了对超清洁双层石墨烯异质结构的输运测量，我们在其中观察到四个四分之一填充态及其相应的莱文-哈尔珀林子态，限制了它们的拓扑序。此外，我们通过检测处于 和 的态完成了半填充平台序列，其女儿态表明了非阿贝尔序的交替序列。这种模式表明存在一个通用的起源，支持它们用于识别偶数分母填充时的拓扑序，不过需要通过直接测量进行进一步确认。观察到的四分之一和半填充态分别出现在 N = 0 和 N = 1 朗道能级中，因此突出了有利于四通量或两通量复合费米子配对态的相互作用之间的竞争。此外，我们观察到几个需要复合费米子之间强相互作用的“下一代”量子霍尔态。
