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arXiv · 2503.12337

Stability of quasi-particle creation and multiband geometry in fractional Chern insulators under magnetic fields

Nozomi Higashino·Yasuhiro Tada
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Abstract

We study creation of quasi-particles in fractional Chern insulators (FCI) 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 quasi-holes and quasi-electrons are stably created by the magnetic fields in the Kapit-Mueller model. On the other hand, stability of the quasi-particle creation depends on directions of the magnetic field in the checkerboard model. Although the quasi-electron creation is stable under a magnetic field, the quasi-hole 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.

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Nozomi Higashino, Yasuhiro Tada. 2025-03-16. Stability of quasi-particle creation and multiband geometry in fractional Chern insulators under magnetic fields. https://doi.org/10.1103/c6zs-m1wk

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