Fractional quantum Hall physics without magnetic field

"Recent experiments on twisted bilayer MoTe2 have reported the first observation of the fractional quantum anomalous Hall effect (FQAHE), demonstrating exotic states with fractionally charged excitations at zero magnetic field. Low-energy continuum descriptions of twisted MoTe2 indicate that its topmost moiré minibands carry non-zero Chern numbers and become almost flat at a magic angle. Additional studies showed that the quantum geometry of the band is nearly ideal at the magic angle, suggesting a connection to the physics of the lowest Landau level that is responsible for the FQAHE stabilization. In this talk I will review recent progress and open challenges in the field of moiré topological order. I will then introduce an approximation to the continuum model that explicitly maps the system to an effective problem of Landau levels in a periodic potential, explaining why magic angles emerge and why the quantum geometry is almost ideal. Finally, I will discuss how our approach might shed light on some of the questions raised by the experiments.

Referencias:

• https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.5.L...
• https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.096602
• https://www.nature.com/articles/s42254-024-00718-z"