Chen Yiwei, Huang Yan, Li Qingxin, Tong Bingbing, Kuang Guangli, Xi Chuanying, Watanabe Kenji, Taniguchi Takashi, Liu Guangtong, Zhu Zheng, Lu Li, Zhang Fu-Chun, Wu Ying-Hai, Wang Lei
National Laboratory of Solid-State Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China.
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
Nat Commun. 2024 Jul 24;15(1):6236. doi: 10.1038/s41467-024-50589-2.
Fractional quantum Hall (FQH) states are exotic quantum many-body phases whose elementary charged excitations are anyons obeying fractional braiding statistics. While most FQH states are believed to have Abelian anyons, the Moore-Read type states with even denominators - appearing at half filling of a Landau level (LL) - are predicted to possess non-Abelian excitations with appealing potential in topological quantum computation. These states, however, depend sensitively on the orbital contents of the single-particle LL wavefunctions and the LL mixing. Here we report magnetotransport measurements on Bernal-stacked trilayer graphene, whose multiband structure facilitates interlaced LL mixing, which can be controlled by external magnetic and displacement fields. We observe robust FQH states including even-denominator ones at filling factors ν = - 9/2, - 3/2, 3/2 and 9/2. In addition, we fine-tune the LL mixing and crossings to drive quantum phase transitions of these half-filling states and neighbouring odd-denominator ones, exhibiting related emerging and waning behaviour.
分数量子霍尔（FQH）态是奇特的量子多体相，其基本带电激发是遵循分数编织统计的任意子。虽然大多数FQH态被认为具有阿贝尔任意子，但出现在朗道能级（LL）半填充时具有偶数分母的摩尔 - 里德型态预计拥有在拓扑量子计算中具有诱人潜力的非阿贝尔激发。然而，这些态敏感地依赖于单粒子LL波函数的轨道内容和LL混合。在此，我们报告了对伯纳尔堆叠三层石墨烯的磁输运测量，其多带结构有利于交错的LL混合，这可以通过外部磁场和位移场来控制。我们观察到了稳健的FQH态，包括在填充因子ν = - 9/2、- 3/2、3/2和9/2时具有偶数分母的态。此外，我们微调LL混合和交叉以驱动这些半填充态和相邻奇数分母态的量子相变，呈现出相关的出现和消失行为。
