Fractional Chern insulator
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Fractional Chern insulators (FCIs) are lattice generalizations of the fractional quantum Hall effect that have been studied theoretically since 1993[1] and have been studied more intensely since early 2010.[2][3] They were first predicted to exist in topological flat bands carrying Chern numbers. They can appear in topologically non-trivial band structures even in the absence of the large magnetic fields needed for the fractional quantum Hall effect. In principle, they can also occur in partially filled bands with trivial band structures if the inter-electron interaction is unusual.[4] They promise physical realizations at lower magnetic fields, higher temperatures, and with shorter characteristic length scales compared to their continuum counterparts.[5][6] FCIs were initially studied by adding electron-electron interactions[7] to a fractionally filled Chern insulator, in one-body models where the Chern band is quasi-flat,[8][9] at zero magnetic field. The FCIs exhibit a fractional quantized Hall conductance.