SFB 1238 | March 05, 14:30
Discovery of the Fractional Quantum Anomalous Hall Effect in Moiré MoTe2
The recent discovery of fractional Chern insulators (FCIs) – lattice analogs of the fractional quantum Hall states – has caused tremendous excitement in the condensed matter community. These topological phases of matter, which have been found in both homobilayer MoTe2 and rhombohedral graphene-hBN moirés, hold great promise for the study of robust anyonic excitations at zero magnetic field. Here, I will discuss experimental work at the University of Washington which established, leveraging both optical and transport probes, the first realization of zero-field fractional Chern insulators in twisted bilayer MoTe2 (tMoTe2).1,2,3 More recent measurements, exploiting the strong coupling between photonic, electronic, and spin degrees of freedom in tMoTe2, have provided additional evidence for the theoretically predicted zero-field composite Fermi liquid near half filling of the flat Chern band.4 While not yet observed experimentally, theory work has predicted FCI phases hosting non-Abelian anyons – crucial building blocks for topologically protected quantum computation – to occur in the system. Given the array of optical and transport measurement tools available to probe tMoTe2, it remains an extremely promising platform for exploring and manipulating these exotic phases of matter.
1. Anderson, E. et al. Programming correlated magnetic states with gate-controlled moiré geometry. Science 381, 325–330 (2023).
2. Cai, J. et al. Signatures of fractional quantum anomalous Hall states in twisted MoTe2. Nature 622, 63–68 (2023).
3. Park, H. et al. Observation of fractionally quantized anomalous Hall effect. Nature 622, 74–79 (2023).
4. Anderson, E. et. al. Trion sensing of a zero-field composite Fermi liquid. Nature 635, 590-595 (2024).
Centre National de la Recherche Scientifique
PH2
Contact: Torsten Röper / Matteo