Recently, both the integer and fractional quantum Hall effect has been observed in twisted bilayer transition metal dichalcogenides (TMDs) at zero magnetic field, generating widespread interest in this materials system. In this talk, I will first briefly review the route towards materials realization of topological states, and then focus on the basic models describing twisted bilayer TMDs, including the origin of the nontrivial topology. I will then discuss how machine learning method can be used to establish the microscopic Hamiltonian and the important role of polarization charges in determining the band topology. Phase diagrams at various fillings as a function of twist angle and gate voltage will be discussed as well.
Reference
- Signatures of fractional quantum anomalous Hall states in twisted MoTe2, Cai et al, Nature 622, 63 (2023)
- Observation of fractionally quantized anomalous Hall effect, Park et al, Nature 622, 74 (2023)
- Fractional Chern insulator in twisted bilayer MoTe2, Wang et al, Phys. Rev. Lett. 132, 036501 (2024)
- Gate-tunable antiferromagnetic Chern insulator in twisted bilayer transition metal dichalcogenides, Liu et al, Phys. Rev. Lett. 132, 146401(2024)
- Polarization-driven band topology evolution in twisted MoTe and WSe2, Zhang et al, Nature Communications 15, 4223 (2024)
- Higher Landau-Level Analogues and Signatures of Non-Abelian States in Twisted Bilayer MoTe2, Wang et al, arXiv: 2404.05697 (Phys. Rev. Lett. Accepted)
- Microscopic signatures of topology in twisted MoTe2, Thompson et al, Nature Physics (accepted)