Emergent Chiral Magnetism in Twisted MoTe₂

Twisted bilayer MoTe₂ has emerged as a highly tunable platform to study unconventional magnetism, topology, and strong correlation in two-dimensional moiré systems. Notably, the first experimental realization of the fractional quantum anomalous Hall effect was seen in rhombohedral-stacked bilayer MoTe₂ with a twist angle of approximately 3.7° [1-2]. As the twist angle varies, interaction between charge carriers can give rise to exotic magnetic phases [3]. Here, we report the observation of chiral spin textures in large angle twisted bilayer MoTe₂. Using reflective magnetic circular dichroism (RMCD) to directly probe the magnetization, we detect clear hysteresis, a hallmark of emergent ferromagnetic ordering near one hole per moiré unit cell at a finite displacement field. Moreover, charge transport measurements demonstrate a gate-tunable topological Hall effect suggesting the presence of non-coplanar spin textures. This intricate spin configuration coincides with a van Hove singularity in the moiré valence band. These findings offer valuable insight into the interplay between topology and magnetism in moiré systems.

[1] J. Cai et al. Signatures of fractional quantum anomalous Hall states in twisted MoTe2. Nature 622, 63–68 (2023).

[2] H. Park et al. Observation of fractionally quantized anomalous Hall effect. Nature 622, 74–79 (2023).

[3] E. Anderson et al., Programming Correlated Magnetic States via Gate Controlled Moiré Geometry, Science 381, 325-330 (2023).