Physics

Nanotechnology

Organic chemistry

Membrane

Scanning tunneling microscope

Crystallography

Ferromagnetism

Epitaxy

van der Waals force

Antiferromagnetism

Bilayer

Chemistry

Materials science

Magnetism

Condensed matter physics

Layer (electronics)

Molecule

Molecular beam epitaxy

Monolayer

Stacking

Biochemistry

Science

Controlling the crystal structure is a powerful approach for manipulating the fundamental properties of solids. In van der Waals materials, this control can be achieved by modifying the stacking order through rotation and translation between the layers. Here, we observed stacking-dependent interlayer magnetism in the two-dimensional (2D) magnetic semiconductor chromium tribromide (CrBr3), which was enabled by the successful growth of its monolayer and bilayer through molecular beam epitaxy. Using in situ spin-polarized scanning tunneling microscopy and spectroscopy, we directly correlate the atomic lattice structure with the observed magnetic order. Although the individual monolayer CrBr3 is ferromagnetic, the interlayer coupling in bilayer depends on the stacking order and can be either ferromagnetic or antiferromagnetic. Our observations pave the way for manipulating 2D magnetism with layer twist angle control.

Direct observation of van der Waals stacking–dependent interlayer magnetism