**Time/Venue** Wednesday, July 27 at 2:00 pm Pacific Timein Physics South 402 and via Zoom:

https://berkeley.zoom.us/j/99523499113pwd=REovb3pyam03WXQwbEhrU3dqNHZvdz09

Meeting ID: 995 2349 9113 Passcode: 600704**Host** Shubhayu Chatterjee/Joel Moore**Title** Moiré Superlattices at Fractional Band Fillings: Fractional Chern Insulators, Particle-Hole duality, and Quantum Geometry**Abstract** We consider the core problem of Coulomb interactions within fractionally filled Moiré flat bands and demonstrate that the dual description in terms of holes, which acquires a non-trivial hole-dispersion, provides key physical intuition and enables more understanding for this strongly correlated problem. We find that the single-hole dispersion has a profound impact on the phase diagram in experimentally relevant examples such as ABC stacked trilayer and twisted bilayer graphene aligned with boron nitride. Such non-trivial particle-hole asymmetry which is generally absent in continuum Landau levels stems from the non-trivial underlying quantum geometry of the Moiré bands. In addition, we predict both twisted bilayer graphene aligned with boron nitride and gate-tunable twisted double bilayer graphene to be versatile platforms for the realization of fractional Chern insulator states like spin-singlet Halperin states and spin-polarized states in bands with Chern number C =1 and C = 2 at zero external magnetic fields.”

[1] Phys. Rev. Lett. 124, 106803 (2020)

[2] Phys. Rev. Lett. 126, 026801 (2021)

[3] arXiv:2202.10467