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arXiv 1102.2658cond-mat.str-el
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朗道能级缺失时的分数量子霍尔效应

Fractional quantum Hall effect in the absence of Landau levels

D. N. Sheng, Zheng-Cheng Gu, Kai Sun, L. Sheng

摘要:

众所周知,具有分数激发的拓扑现象,即,当电子在朗道能级上运动时,将出现分数量子霍尔效应(Fractional \cite{Tsui1982})。在这封信中,我们报告了在相互作用费米子模型中,在朗道能级缺失的情况下,发现了量子阱。我们的哈密顿量的非相互作用部分是最近提出的棋盘格点\cite{sun}上的拓扑非平凡的平带模型。在最近邻排斥($U$)的存在下,我们发现在1/3填充时,费米液体态是不稳定的。然而,在1/5填充时,当$U$不太强时,需要次近邻排斥来发生1/5反相。我们证明了这些新的状态的特征,并确定相应的相图。

英文摘要:

It has been well-known that topological phenomena with fractional excitations, i.e., the fractional quantum Hall effect (FQHE) \cite{Tsui1982} will emerge when electrons move in Landau levels. In this letter, we report the discovery of the FQHE in the absence of Landau levels in an interacting fermion model. The non-interacting part of our Hamiltonian is the recently proposed topologically nontrivial flat band model on the checkerboard lattice \cite{sun}. In the presence of nearest-neighboring repulsion ($U$), we find that at 1/3 filling, the Fermi-liquid state is unstable towards FQHE. At 1/5 filling, however, a next-nearest-neighboring repulsion is needed for the occurrence of the 1/5 FQHE when $U$ is not too strong. We demonstrate the characteristic features of these novel states and determine the phase diagram correspondingly.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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