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Journal article
Fractional Chern insulator on a triangular lattice of strongly correlated t sub(2)g electrons
Physical review. B, Condensed matter and materials physics, v 86(23)
15 Dec 2012
Abstract
We discuss the low-energy limit of three-orbital Kondo-lattice and Hubbard models describing t sub(2)g orbitals on a triangular lattice near half-filling. We analyze how very flat single-particle bands with nontrivial topological character, a Chern number C = + or -1, arise both in the limit of infinite on-site interactions as well as in more realistic regimes. Exact diagonalization is then used to investigate an effective one-orbital spinless-fermion model at fractional fillings including nearest-neighbor interaction V; it reveals signatures of fractional Chern insulator (FCI) states for several filling fractions. In addition to indications based on energies, e.g., flux insertion and fractional statistics of quasiholes, Chern numbers are obtained. It is shown that FCI states are robust against disorder in the underlying magnetic texture that defines the topological character of the band. We also investigate competition between a FCI state and a charge density wave (CDW) and discuss the effects of particle-hole asymmetry and Fermi-surface nesting. FCI states turn out to be rather robust and do not require very flat bands, but can also arise when filling or an absence of Fermi-surface nesting disfavor the competing CDW. Nevertheless, very flat bands allow FCI states to be induced by weaker interactions than those needed for more dispersive bands.
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Details
- Title
- Fractional Chern insulator on a triangular lattice of strongly correlated t sub(2)g electrons
- Creators
- Stefanos KourtisJorn VenderbosMaria Daghofer
- Publication Details
- Physical review. B, Condensed matter and materials physics, v 86(23)
- Publisher
- Cold Spring Harbor Press
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000312291900003
- Scopus ID
- 2-s2.0-84871041955
- Other Identifier
- 991021865924204721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Materials Science, Multidisciplinary
- Physics, Applied
- Physics, Condensed Matter