Fractional Chern insulators beyond Laughlin states

Tianhan Liu, C. Repellin, B. Andrei Bernevig, N. Regnault

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

We report the first numerical observation of composite fermion (CF) states in fractional Chern insulators (FCI) using exact diagonalization. The ruby lattice Chern insulator model for both fermions and bosons exhibits a clear signature of CF states at filling factors 2/5 and 3/7 (2/3 and 3/4 for bosons). The topological properties of these states are studied through several approaches. Quasihole and quasielectron excitations in FCI display similar features as their fractional quantum hall (FQH) counterparts. The entanglement spectrum of FCI ground states shows an identical fingerprint to its FQH partner. We show that the correspondence between FCI and FQH obeys the emergent symmetry already established, proving the validity of this approach beyond the clustered states. We investigate other Chern insulator models and find similar signatures of CF states. However, some of these systems exhibit strong finite size effects.

Original languageEnglish (US)
Article number205136
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume87
Issue number20
DOIs
StatePublished - May 29 2013

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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