Regensburg 2025 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 19: Focus Session: Strongly Correlated Quantum States in Moire Heterostructures (joint session TT/HL/MA)
HL 19.7: Talk
Tuesday, March 18, 2025, 12:30–12:45, H36
Single-Particle Spectral Function of Fractional Quantum Anomalous Hall States — •Fabian Pichler1,2, Wilhelm Kadow1,2, Clemens Kuhlenkamp3,1,2, and Michael Knap1,2 — 1Technical University of Munich, TUM School of Natural Sciences, Garching, Germany — 2Munich Center for Quantum Science and Technology (MCQST), München, Germany — 3Department of Physics, Harvard University, Cambridge, Massachusetts, USA
Fractional quantum Hall states are the most prominent example of states with topological order, hosting excitations with fractionalized charge. Recent experiments in twisted MoTe2 and graphene-based heterostructures provide evidence of fractional quantum anomalous Hall (FQAH) states, which spontaneously break time-reversal symmetry and persist even without an external magnetic field. Understanding the unique properties of these states requires the characterization of their low-energy excitations. To that end, we construct a parton theory for the energy and momentum-resolved single-particle spectral function of FQAH states. We explicitly consider several experimentally observed filling fractions as well as a composite Fermi liquid in the half-filled Chern band. The parton description captures qualitatively our numerical exact diagonalization results. Additionally, we discuss how the finite bandwidth of the Chern band and the non-ideal quantum geometry affect the fractionalized excitations. Our work demonstrates that the energy and momentum-resolved electronic single-particle spectral function provides a valuable tool to characterize fractionalized excitations of FQAH states in moiré lattices.
Keywords: Fractional Quantum Anomalous Hall Effect; Quantum Twisting Microscope; moiré heterostructure; Fractional Chern Insulator; Partons