Researchers synthesize highly-ordered topological semimetal thin films via sputtering technology

A team of scientists from the University of Minnesota Twin Cities has synthesized a thin film of a unique topological semimetal material that has the potential to generate more computing power and memory storage while using significantly less energy. The researchers were also able to closely study the material, leading to some fascinating findings about the physics behind its unique properties.

Much attention is put into developing the materials that power electronic devices. While traditional semiconductors are the technology behind most of today's computer chips, scientists are always looking for new materials that can generate more power with less energy to make electronics better, smaller, and more efficient. One such candidate for these new and improved computer chips is a class of quantum materials called topological semimetals. The electrons in these materials behave in different ways, giving the materials unique properties that typical insulators and metals used in electronic devices do not have. For this reason, they are being explored for use in spintronic devices, an alternative to traditional semiconductor devices that leverage the spin of electrons rather than the electrical charge to store data and process information.


In this recent study, an interdisciplinary team of University of Minnesota researchers were able to successfully synthesize such a material as a thin film -- and prove that it has the potential for high performance with low energy consumption.

"This research shows for the first time that you can transition from a weak topological insulator to a topological semimetal using a magnetic doping strategy," said Jian-Ping Wang, a senior author of the paper and a Distinguished McKnight University Professor and Robert F. Hartmann Chair in the University of Minnesota Department of Electrical and Computer Engineering. "We're looking for ways to extend the lifetimes for our electrical devices and at the same time lower the energy consumption, and we're trying to do that in non-traditional, out-of-the-box ways."

Researchers have been working on topological materials for years, but the University of Minnesota team is the first to use a patented, industry-compatible sputtering process to create this semimetal in a thin film format. Because their process is industry compatible, Wang said, the technology can be more easily adopted and used for manufacturing real-world devices.

"Every day in our lives, we use electronic devices, from our cell phones to dishwashers to microwaves. They all use chips. Everything consumes energy," said Andre Mkhoyan, a senior author of the paper. "The question is, how do we minimize that energy consumption? This research is a step in that direction. We are coming up with a new class of materials with similar or often better performance, but using much less energy."

Since the researchers fabricated such a high-quality material, they were also able to closely analyze its properties and what makes it so unique.

"One of the main contributions of this work from a physics point of view is that we were able to study some of this material's most fundamental properties," said Tony Low, a senior author of the paper. "Normally, when you apply a magnetic field, the longitudinal resistance of a material will increase, but in this particular topological material, we have predicted that it would decrease. We were able to corroborate our theory to the measured transport data and confirm that there is indeed a negative resistance."

Low, Mkhoyan, and Wang have been working together for more than a decade on topological materials for next generation electronic devices and systems - this research wouldn't have been possible without combining their respective expertise in theory and computation, material growth and characterization, and device fabrication.

"It not only takes an inspiring vision but also great patience across the four disciplines and a dedicated group of team members to work on such an important but challenging topic, which will potentially enable the transition of the technology from lab to industry," Wang said.

Posted: Jul 15,2023 by Roni Peleg