Reviewed by Lexie CornerMay 2 2024
A team of international researchers from the University of Wyoming found an inventive technique to regulate ultrathin, two-dimensional (2D) van der Waals magnets' minuscule magnetic states. This technique works similarly to how a light switch operates to control a lightbulb. The research was published in the journal Nature Communications.
Jifa Tian Image Credit: University of Wyoming
Imagine a future where computers can learn and make decisions in ways that emulate human thinking, yet with a speed and efficiency that far surpass the current capability of computers by orders of magnitude.
Jifa Tian, Assistant Professor, Department of Physics and Astronomy, University of Wyoming, said, "Our discovery could lead to advanced memory devices that store more data and consume less power or enable the development of entirely new types of computers that can quickly solve problems that are currently intractable."
Tian is also an Interim Director of UW’s Center for Quantum Information Science and Engineering.
Van der Waals materials consist of tightly bonded 2D layers weakly bound in the third dimension by van der Waals forces. Graphite, a van der Waals material, finds widespread industrial applications in electrodes, lubricants, fibers, heat exchangers, and batteries. The nature of the van der Waals forces between layers enables researchers to use Scotch tape to peel the layers into atomic thickness.
The group created a device called a magnetic tunnel junction, which consists of two layers of graphene sandwiched over chromium triiodide, a 2D insulating magnet only a few atoms thick.
Tian explains that by passing a minuscule electric current, known as a tunneling current, through this sandwich structure, the orientation of the magnetic domains (approximately 100 nm in size) within the individual chromium triiodide layers can be controlled.
Specifically, this tunneling current not only can control the switching direction between two stable spin states but also induces and manipulates switching between metastable spin states, called stochastic switching.
ZhuangEn Fu, Postdoctoral Fellow, University of Maryland
Tian said, “This breakthrough is not just intriguing; it is highly practical. It consumes three orders of magnitude less energy than traditional methods, akin to swapping an old lightbulb for an LED, marking it a potential game-changer for future technology.”
Our research could lead to the development of novel computing devices that are faster, smaller, and more energy-efficient and powerful than ever before. Our research marks a significant advancement in magnetism at the 2D limit and sets the stage for new, powerful computing platforms, such as probabilistic computers.
Jifa Tian, Assistant Professor, Department of Physics and Astronomy, University of Wyoming
Bits, or 0s and 1s, are used in traditional computers to store information. This binary code is the basis of all traditional computing operations. The processing capacity of quantum computers increases exponentially because they employ quantum bits, which may simultaneously represent the numbers “0” and “1.”
Tian said, “In our work, we have developed what you might think of as a probabilistic bit, which can switch between ‘0’ and ‘1’ (two spin states) based on the tunneling current controlled probabilities; these bits are based on the unique properties of ultrathin 2D magnets and can be linked together in a way that is similar to neurons in the brain to form a new kind of computer, known as a probabilistic computer.”
Tian concluded, “What makes these new computers potentially revolutionary is their ability to handle tasks that are incredibly challenging for traditional and even quantum computers, such as certain types of complex machine learning tasks and data processing problems; they are naturally tolerant to errors, simple in design and take up less space, which could lead to more efficient and powerful computing technologies.”
To clarify how tunneling currents affect spin states in the 2D magnetic tunnel junctions, Hua Chen, an Associate Professor of Physics at Colorado State University, and Allan MacDonald, a Professor of Physics at the University of Texas-Austin, worked together to construct a theoretical model. Additional contributions were received from Penn State University, Northeastern University, and the National Institute for Materials Science in Namiki, Tsukuba, Japan.
The research was sponsored by the US Department of Energy; Wyoming NASA EPSCoR (Established Program to Stimulate Competitive Research); the National Science Foundation; and the World Premier International Research Center Initiative and the Ministry of Education, Culture, Sports, Science, and Technology, both in Japan.