paper

Variational Mapping of Chern Bands to Landau Levels: Application to Fractional Chern Insulators in Twisted MoTe

arXiv:2405.20307 · doi:10.1103/PhysRevB.111.125122

Abstract

We present a theoretical study of mapping between Chern bands and generalized Landau levels in twisted bilayer MoTe (MoTe), where fractional Chern insulators down to zero magnetic fields have been observed. We construct an exact Landau-level representation of moiré bands, where the basis functions, characterized by a uniform quantum geometry, are derived from Landau-level wavefunctions dressed by spinors aligned or antialigned with the layer pseudospin skyrmion field. We further generalize the dressed zeroth Landau level to a variational wavefunction with an ideal yet nonuniform quantum geometry and variationally maximize its weight in the first moiré band. The variational wavefunction has a high overlap with the first band and quantitatively captures the exact diagonalization spectra of fractional Chern insulators at hole-filling factors and , providing a clear theoretical mechanism for the formation and properties of the fractionalized states. Our work introduces a variational approach to studying fractional states by mapping Chern bands to Landau levels, with application to other systems beyond MoTe also demonstrated.

13 pages, 9 figures. Published in Physical Review B as Editors' Suggestion

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