Stability of quasiparticle creation and multiband quantum geometry in fractional Chern insulators under magnetic fields
Phys. Rev. B 111, 245154 – Published 25 June, 2025
DOI: https://doi.org/10.1103/c6zs-m1wk
Abstract
We study creation of quasiparticles in fractional Chern insulators (FCIs) under magnetic fields. We consider two representative models, the Kapit-Mueller model and the checkerboard model, which have distinct band properties in terms of the quantum geometry. The former satisfies the so-called ideal condition and well mimics the lowest Landau level, while the latter is not ideal for realization of FCI states. It is found within exact diagonalization that both quasiholes and quasielectrons are stably created by the magnetic fields in the Kapit-Mueller model. On the other hand, stability of the quasiparticle creation depends on directions of the magnetic field in the checkerboard model. Although the quasielectron creation is stable under a magnetic field, the quasihole creation and the underlying FCI state are unstable for the opposite field direction, leading to a field-induced non-FCI state. We point out that this difference can be understood based on the multiband quantum geometry in the presence of the magnetic fields.
