New magnetism: kinetic ferromagnetism

A team of physicists has discovered a new type of magnetism called “kinetic ferromagnetism”. This magnetism is caused by the movement of electrons, not by their interactions with each other. The researchers made the discovery by studying a material made of two thin sheets of atoms stacked together to form an intricate pattern called a moiré lattice.

The moiré lattice is what makes the material magnetic. The extra electrons in the lattice delocalize and spread out, forming two-electron combinations called doublons. These doublons cannot delocalize unless the electrons in the surrounding lattice sites all have aligned spins. As the material relentlessly pursues its lowest-energy state, the end result is that doublons tend to create small, localized ferromagnetic regions.

This is the first time that kinetic ferromagnetism has been seen in an extended system. The previous examples of kinetic ferromagnetism were found in very small systems, such as a system with just three electrons.

The researchers hope that their discovery can lead to new applications for magnetism, such as new types of electronic devices.

Read the whole article here:

https://www.quantamagazine.org/new-kind-of-magnetism-spotted-in-an-engineered-material-20240110/