Tianhan Liu, C. Repellin, B. Andrei Bernevig, N. Regnault
We report the first numerical observation of composite fermion (CF) states in fractional Chern insulators (FCI) using exact diagonalization. Two Chern insulator models (the Kagome and ruby lattices) for both fermions and bosons exhibit 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 groundstates 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. Unexpectedly, we observe that FCI hosting clear Laughlin-like states may not lead to stable CF states unlike the continuum FQH case.
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http://arxiv.org/abs/1206.2626
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