A thin sandwich made of two different materials. You run an electric current through it, and the top slice magnetizes in one direction, the bottom in the opposite. This isn't a magic trick; it's the layer Edelstein effect, just described by physicists.
In everyday life, electricity and magnetism are closely linked, but controlling magnetization with a current is no easy feat. Here, the very nature of the two-layer system steps in: the crystal symmetry makes electrons on different layers start to "spin" (change their spin: their intrinsic rotation) in opposite directions. A difference in magnetic moments arises between the layers, and no external magnets are needed.
The authors tested the idea on real materials: they stacked pairs of MoSSe, MoTe₂, and WTe₂ layers and confirmed via computer simulations — the effect is real and universal. Moreover, a weak external field can switch on additional components of magnetization, like a toggle. This gives birth to a tool for ultra-compact future electronics.
An electron's spin can be imagined as a tiny compass needle. In the layer Edelstein effect, these needles on different layers point in opposite directions, even though the material as a whole remains non-magnetic.