Physics professor Jeffrey Rau's research into a new type of magnetism has caught the attention of the pre-eminent journal Physical Review Letters. One of his latest publications was not only featured in the journal, but was selected for its "Collection of the Year 2024" list.
"Out of the 2,000 to 2,500 published papers, which are already the best in all of physics, they pick about 60 or so to be the best of the best, and Professor Rau's was one of those," says Steven Rehse, head of the Department of Physics.
Illustration of the key features of altermagnetic manganese telluride.
"This is a huge accomplishment for an early career researcher, as this paper has the potential to be a seminal work in the field of magnetism and is already being recognized as such."
Dr. Rau says there are two main dominant forms of magnetism. Ferromagnets the kind that stick to your fridge and antiferromagnets which, while magnetic, are arranged oppositely at the atomic level, and so their magnetic fields cancel out and they do not stick to things.
In the last few years, physicists have proposed a new kind of magnetism called altermagnetism. Altermagnets do not stick to your fridge, but they do share some of the positive properties of both ferromagnets and antiferromagnets.
The article, "Landau Theory of Altermagnetism," which was written by Rau and his France-based collaborator Paul McClarty, explores how this new topic fits into the broader field of magnetism. Altermagnets, Rau says, have attracted interest because this mix of properties may have technological applications in a field called spintronics.
"Currently most information technology is based on electrical currents moving through devices such as transistors, diodes, or other integrated circuits, but these necessarily come with dissipation, or loss of energy. Resistance to the flow of that current generates heat limiting their efficiency and often how fast you can run these things. Spin currents, which manipulate the electron's spin instead, suffer significantly less from this kind of dissipation," he says.
"The hope would be, if you could design and build devices using these materials if you could somehow figure out how to manipulate spin currents and use them to process information instead then you could build devices that use significantly less power, making them much more efficient."
The field of spintronics is still in the basic research stage, but Rau says it definitely has potential. His research was driven by the need to shine a light on the complicated topic.
"We tried to clarify it to ourselves and came up with a simpler description of it based on the symmetries of the problem," says Rau.
"We essentially wrote this paper to show how many of the properties of this new kind of magnet are connected, and people seem to find it useful, so we're pretty happy about it."
