Fractional quantum anomalous Hall states in twisted bilayer MoTe2 and WSe2

Abstract
We demonstrate via exact diagonalization that AA-stacked transition metal dichalcogenide homobilayers host fractional quantum anomalous Hall (FQAH) states with fractionally quantized Hall conductance at fractional fillings n=13,23 and zero magnetic field. While both states are most robust at angles close to 2-degree, the n=13 state gives way to a charge density wave with increasing twist angle whereas the n=23 state survives across a much broader range of twist angles. We show that the competition between FQAH states and charge density wave or metallic phases is primarily controlled by the wave functions and dispersion of the underlying Chern band, respectively. Additionally, Ising ferromagnetism is found across a broad range of fillings where the system is insulating or metallic alike. The spin gap is enhanced at filling fractions where integer and fractional quantum anomalous Hall states are formed.

Citation
Reddy, A. P., Alsallom, F., Zhang, Y., Devakul, T., & Fu, L. (2023). Fractional quantum anomalous Hall states in twisted bilayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">mml:msubmml:miMoTe</mml:mi>mml:mn2</mml:mn></mml:msub></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">mml:msubmml:miWSe</mml:mi>mml:mn2</mml:mn></mml:msub></mml:math>. Physical Review B, 108(8). https://doi.org/10.1103/physrevb.108.085117

Acknowledgements
We thank X. Xu for collaboration on a closely related experiment on , B. Foutty and B. Feldman for collaboration on a closely related experiment on , V. Crépel for previous collaboration on related theoretical works , as well as D. Luo and P. Ledwith for helpful discussions. This work was supported by the Air Force Office of Scientific Research (AFOSR) under Award No. FA9550-22-1-0432 and the David and Lucile Packard Foundation. Y.Z. acknowledges support from the start-up fund at the University of Tennessee. F.A acknowledges support from the KAUST Gifted Students Program and the Undergraduate Research Opportunities Program at MIT.

Publisher
American Physical Society (APS)

Journal
Physical Review B

DOI
10.1103/PhysRevB.108.085117

arXiv
2304.12261

Additional Links
https://link.aps.org/doi/10.1103/PhysRevB.108.085117

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