Evidence for a fractional fractal quantum Hall effect in graphene superlattices

Lei Wang, Yuanda Gao, Bo Wen, Zheng Han, Takashi Taniguchi, Kenji Watanabe, Mikito Koshino, James Hone, Cory R. Dean

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71 Citations (Scopus)

Abstract

The Hofstadter energy spectrum provides a uniquely tunable system to study emergent topological order in the regime of strong interactions. Previous experiments, however, have been limited to low Bloch band fillings where only the Landau level index plays a role.We report measurements of high-mobility graphene superlattices where the complete unit cell of the Hofstadter spectrum is accessible.We observed coexistence of conventional fractional quantum Hall effect (QHE) states together with the integer QHE states associated with the fractal Hofstadter spectrum. At large magnetic field, we observed signatures of another series of states, which appeared at fractional Bloch filling index.These fractional Bloch band QHE states are not anticipated by existing theoretical pictures and point toward a distinct type of many-body state.

Original languageEnglish
Pages (from-to)1231-1234
Number of pages4
JournalScience
Volume350
Issue number6265
DOIs
Publication statusPublished - 2015 Dec 4

ASJC Scopus subject areas

  • General

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    Wang, L., Gao, Y., Wen, B., Han, Z., Taniguchi, T., Watanabe, K., Koshino, M., Hone, J., & Dean, C. R. (2015). Evidence for a fractional fractal quantum Hall effect in graphene superlattices. Science, 350(6265), 1231-1234. https://doi.org/10.1126/science.aad2102