An extension of the cell-construction method for the flat-band ferromagnetism

Abstract

We present an extension of the cell-construction method for the flat-band ferromagnetism. In a rather general setting, we construct Hubbard models with highly degenerate single-electron ground states and obtain a formal representation of these single-electron ground states. By our version of the cell-construction method, various types of flat-band Hubbard models, including the one on line graphs, can be designed and shown to have the unique ferromagnetic ground states when the electron number is equal to the degeneracy of the single-electron ground states.

23 pages, 8 figures. Ver2: minor revision, typos corrected

References in corpus (3)

• Stability of Ferromagnetism in Hubbard Models with Nearly-Flat Bands
• Systematic construction of topological flat-band models by molecular-orbital representation
• Ferromagnetism in the Hubbard model with a gapless nearly-flat band

Cited by in corpus (8)

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• Line-graph-lattice crystal structures of stoichiometric materials
• Symmetry-protected Topological Phases in Spinful Bosons with a Flat Band
• Non-ergodic one-magnon magnetization dynamics of the antiferromagnetic delta chain
• Hund's coupling-assisted ferromagnetic percolation transition in a multiorbital flat band
• Construction of interacting flat-band models by molecular-orbital representation: Correlation functions, energy gap, and entanglement
• Flat-band ferromagnetism in the SU($N$) Hubbard and Kondo lattice models
• Robust Flat Bands with Tunable Energies in Honeycomb Superlattices