Intertwined magnetism, correlations and topology in semiconductor moiré materials

Semiconductor moiré lattices provide a flexible platform to study flat, topological bands with a variety of closely competing ground states. In this talk, I will describe single-electron transistor microscopy of twisted WSe2 which reveals a rich interplay between magnetism, correlations, and topology. At zero magnetic field, we observe quantum anomalous Hall states and demonstrate topological phase transitions as a function of twist angle and electric field. In the Hofstadter regime at high magnetic field, a cascade of magnetic phase transitions emerges due to crossing Hofstadter and moiré bands of differing spin. I will discuss which experimental tuning knobs are most influential in determining the preferred ground states, clarifying the respective roles played by material and moiré properties in shaping the observed symmetry breaking in different physical regimes.

Speaker: Ben Feldman, Stanford University