Report on scipost_202207_00033v1
Year: 2022
Type: peer-review
Abstract: We study the many-body physics in twisted bilayer graphene coupled to periodic driving of a circularly polarized light when electron-electron interactions are taken into account.In the limit of high driving frequency Ω, we use Floquet theory to formulate the system by an effective static Hamiltonian truncated to the order of Ω -2 , which consists of a singleelectron part and the screened Coulomb interaction.We numerically simulate this effective Hamiltonian by extensive exact diagonalization in the parameter space spanned by the twist angle and driving strength.Remarkably, in a wide region of the parameter space, we identify Floquet fractional Chern insulator states in the partially filled Floquet valence band.We characterize these topologically ordered states by ground-state degeneracy, spectral flow, and entanglement spectrum.In regions of the parameter space where fractional Chern insulator states are absent, we find topologically trivial charge density waves and interaction-induced Fermi liquid which strongly compete with fractional Chern insulator states.
Authors: Peng-Sheng Hu, Zhao Liu
Institution: Zhejiang University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Awards: G5364026802, G5452418588
OpenAlex ID: W4387758783