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Hofstadter butterflies for flat bands

Hideo Aoki·Masato Ando·Hajime Matsumura
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Abstract

Hofstadter's diagram, or the energy spectrum against the magnetic field in tight-binding systems, is obtained for the models having flat (dispersionless) one-electron band(s) that have originally been proposed for itinerant spin ferromagnetism. Magnetic fields preserve those flat bands that arise from a topological reason, while dispersions emerge in a singular manner for the flat bands arising from interference, implying an anomalous orbital magnetism.

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Hideo Aoki, Masato Ando, Hajime Matsumura. 1996-07-31. Hofstadter butterflies for flat bands. https://doi.org/10.1103/physrevb.54.r17296

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