Materials scientists aim to control the crystal structure of a solid—in a powerful approach to manipulate their fundamental properties. Researchers can achieve this control in van der Waals (vDW) materials by modifying the stacking order through rotation and translation between the vDW layers. In a recent study published in Science, Weijong Chen and a research team in the interdisciplinary departments of physics, advanced materials, nanoelectronics devices and quantum computing, and materials science and engineering in China and the U.S. observed stacking-dependent interlayer magnetism in the two-dimensional magnetic semiconductor chromium tribromide (CrBr3).
They achieved this through the successful growth of a monolayer and bilayer of the material using molecular beam epitaxy (MBE). The researchers used in situ spin-polar scanning tunneling microscopy and spectroscopy to directly correlate the atomic lattice structure with the observed magnetic order. They observed the individual monolayer of CrBr3 to be ferromagnetic but the interlayer coupling in the bilayer depended on the stacking order to either be ferromagnetic or antiferromagnetic. Observations made in the work will pave the way to manipulate 2-D magnetism with layer twist angle control.
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