Researchers from Tohoku University in Japan, University of California Riverside and the Massachusetts Institute of Technology detail a decade of research advancements in the emerging field of antiferromagnetic spintronics that holds the promise of moving beyond today’s world of electrons moving through semiconductors.
As computers and other electronic devices become faster and more powerful, they are coming closer to a physical limitation caused by heat generated by the electrons that carry information as they move through semiconductors. “Making heat is a fundamental limit that will prevent the further development of electronic devices. So, we are basically hitting a bottleneck because our computers are way faster than they used to be two decades ago,” said Ran Cheng, an assistant professor of electrical and computer engineering with UCR’s Bourns College of Engineering. Workarounds like cooling systems can go only so far as artificial intelligence, machine learning, video streaming, and other applications demand faster and faster computer processing and memory retrievals.
The team envisions a future in which information will travel without generating significant heat in the form of magnons, which are fundamental quantum units of spinning magnetic moments. Since magnetic moments can spin in different directions along anchored axes, their quantum excitations – magnons – could be used to encode and transfer information in the binary language that sets up the basis of today’s computing.
“For binary operation, we just encode zeroes and ones in the counterclockwise and clockwise rotations of the magnetic moments,” said UCR's Ran Cheng. “But the exciting thing is that with using the antiferromagnetic insulators, we can also possibly move and process quantum information, which goes beyond simply zeroes and ones.”
Besides energy saving and quantum operation, antiferromagnetic spintronics also offers a great speed advantage over semiconductor electronics. The technology could allow computer processing or memory saving and retrievals to be done at speeds a hundred times faster than electrons moving through semiconductors. If electrons achieve the same level of performance by traveling extremely fast through semiconductors, the enormous amount of heat generated would make your cellphone, laptop, or desktop computer would simply melt, Cheng said.
The recent paper describes a series of crucial findings in coherent antiferromagnetic spintronics, including spin generation and transport, electrically driven spin rotation, and related ultrafast spintronic effects. The paper further outlines areas in immediate attention for the technology to have practical applications. This includes finding ways to interface the fast transfer of information to other components of devices, the visualization of magnetic switching processes, and the exploration of novel quantum effects of magnons.
“When we try to integrate the magnons with other integrated circuits, we are going to have to make the interface perfect,” Cheng said. “So, I think that there's still a lot of practical problems that we need to solve in the near future.”