Evidence of competing ground states between fractional Chern insulator and antiferromagnetism in moiré MoTe2

Moiré materials—formed by stacking atomically thin crystals with a small twist—create tunable electronic lattices where strong interactions and band topology can generate unusual magnetic and topological phases. In twisted bilayer MoTe2, ferromagnetism has been closely linked to integer and fractional Chern insulators, while the true zero‑field ground state can be sensitive to twist angle and vertical electric field. Here we show that devices with intermediate twist angle (~3°) may host antiferromagnetic ordered ground states at fixed hole fillings of 1 and 2/3, evidenced by suppressed zero‑field magneto‑optical and Hall responses and field‑driven transitions into quantized Chern states. By tuning only the vertical electric field, we reversibly switch the system from antiferromagnetism to ferromagnetism accompanied by integer or fractional Chern insulating behavior near the layer‑polarization threshold, and then to a paramagnetic regime at larger fields. These results reveal competing correlated ground states in a single moiré platform and establish electric‑field control of magnetism and topology. Chern ferromagnetism is established in twisted bilayer MoTe2 devices at large twist angles. Here, the authors observe evidence of antiferromagnetic ground states with zero Hall resistance at an intermediate twist angle around three degrees, demonstrating the sensitivity of the magnetic ground state.