biostudies-literatureKnuppel PNational Science Foundation (NSF)MEXT | JST | Core Research for Evolutional Science and Technology (CREST)United States Department of Defense | United States Air Force | AFMC | Air Force Office of Scientific Research (AF Office of Scientific Research)1959https://www.ebi.ac.uk/biostudies/studies/S-EPMC11861663biostudies-literatureUnknown16(1)Twisted transition metal dichalcogenide (TMD) bilayers have enabled the discovery of superconductivity, ferromagnetism, correlated insulators, and a series of new topological phases of matter. However, the connection between these electronic phases of matter and the underlying band structure singularities has remained largely unexplored. Here, combining magnetic circular dichroism and exciton sensing measurements, we investigate the influence of a van Hove singularity (vHS) on the correlated phases in bilayer WSe₂ with twist angle between 2 and 3 degrees. By tuning the vHS across the Fermi level using electric and magnetic fields, we observe Stoner ferromagnetism below moiré lattice filling one and Chern insulators at filling one. The experimental observations are supported by the continuum model band structure calculations. Our results highlight the prospect of engineering electronic phases of matter in moiré materials by tunable van Hove singularities.Nature communicationsCorrelated states controlled by a tunable van Hove singularity in moire WSe₂ bilayers.PMC11861663DMR-1807810FA9550-20-1-0219DMR-2114535JPMJCR15F3FA9550-19-1-0390Xia YXia ZZhu JShan JKnuppel PMak KFWatanabe KHan ZZeng YTaniguchi TfalseCorrelated states controlled by a tunable van Hove singularity in moire WSe₂ bilayers.Twisted transition metal dichalcogenide (TMD) bilayers have enabled the discovery of superconductivity, ferromagnetism, correlated insulators, and a series of new topological phases of matter. However, the connection between these electronic phases of matter and the underlying band structure singularities has remained largely unexplored. Here, combining magnetic circular dichroism and exciton sensing measurements, we investigate the influence of a van Hove singularity (vHS) on the correlated phases in bilayer WSe₂ with twist angle between 2 and 3 degrees. By tuning the vHS across the Fermi level using electric and magnetic fields, we observe Stoner ferromagnetism below moiré lattice filling one and Chern insulators at filling one. The experimental observations are supported by the continuum model band structure calculations. Our results highlight the prospect of engineering electronic phases of matter in moiré materials by tunable van Hove singularities.2025-01-01T00:00:00Z2025 Feb2025-04-04T10:41:57.878Z2025-04-04T10:41:57.878ZS-EPMC118616634000064610.1038/s41467-025-57235-5