An Atom-Thick Magnet: Power in a Single Layer express
A monolayer of FeCl2 on Au(111) was studied by spin-polarized scanning tunneling microscopy. Ferromagnetic ordering was observed with a band gap of 3.3 eV and a strongly spin-polarized conduction band emerging 1.5 eV above the Fermi level. Triangular atomic defects have a decisive influence on the electronic structure: within a 1.6 nm radius around each defect, the conduction band is locally suppressed, and the tunneling magnetoconductivity drops by a factor of four. Atomically resolved hysteresis loops were recorded, demonstrating a soft ferromagnetic ground state with pronounced easy-axis anisotropy out of plane and coercive fields in the range of 15–50 mT. The results confirm the promise of FeCl2 for creating van der Waals heterostructures.
Each electron is a tiny magnet. In a single-atom-thick layer of iron chloride, they all align in the same direction, like dancers in a perfectly synchronized routine. Nature usually avoids such order (that's high entropy), but quantum forces compel them to comply.
Using a special microscope that "sees" the spin of each atom, scientists proved that this layer is a real magnet, switchable with a tiny voltage.
The most striking fact: chemically, it's almost rust. But while a rusty nail is useless, the single-atom layer opens the door to spintronics—electronics where information is carried not by charge but by magnetic state, promising ultra-fast and energy-efficient devices. The ideas of magnetism pioneers Heisenberg and Pauli have found an unexpected embodiment in this two-dimensional material.
🎯 Iron chloride is chemically very similar to common rust, but as a monolayer it transforms into a quantum magnet with amazing properties.