A University of Minnesota-Twin Cities research team has synthesized for the first time a unique topological semi-metallic material film that has the potential to produce greater computing power and memory storage while dramatically reducing energy consumption. In addition, the team studied the material carefully and gained important insights into the physics behind its unique properties.
The research was recently published in the journal Nature Communications.
As evidenced by the recent CHIPS and Science Act in the United States, there is a growing need to increase semiconductor manufacturing and support research used to develop the materials that power electronic devices everywhere. While traditional semiconductors are the technology behind most computer chips today, scientists and engineers are always looking for new materials that can produce more power with less to make electronics better, smaller, and more efficient.
One candidate material for this new class of 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 not found in typical insulators and metals used in electronic devices. Therefore, these materials are being explored for use in spintronic devices. Spintronic devices are an alternative to traditional semiconductor devices that use the spin of electrons instead of electric charge to store data and process information.
In the new study, an interdisciplinary research team at the University of Minnesota successfully synthesized such a thin film material and demonstrated its potential for high performance and low energy consumption.
"This study shows for the first time that it is possible to transition from a weak topological insulator to a topological semimetal using a magnetic doping strategy," said Jianping Wang, senior author of the paper, Distinguished Professor at McKnight University and Robert Hartmann Chair Professor in the Department of Electrical and Computer Engineering at the University of Minnesota. "We are looking for ways to extend the life of electronic devices while reducing energy consumption, and we are trying to use non-traditional, unconventional methods to achieve this goal."
Researchers have been studying 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 thin film form. Wang said that because their process is compatible with industry, the technology could be more easily adopted and used to make real-world devices.
"We use electronic devices every day in our lives, from cell phones to dishwashers to microwave ovens. They all use chips. Everything consumes energy," said Andre Mkhoyan, the paper's senior author and the Ray D. and Mary T. Johnson Professor of Chemical Engineering and Materials Science at the University of Minnesota. "The question is, how do we minimize energy consumption? This research is a step in that direction. We are developing a new class of materials with similar or even better properties, but with lower energy consumption."
Because the researchers created such a high-quality material, they were also able to carefully analyze its properties and what makes it unique.
"From a physics perspective, one of the major contributions of this work is that we were able to study some of the most fundamental properties of this material," said Tony Low, senior author of the paper and the Paul Palmberg Associate Professor in the Department of Electrical and Computer Engineering at the University of Minnesota. "Normally, when you apply a magnetic field, the longitudinal resistance of the material increases, but in this particular topological material, we predicted that the longitudinal resistance would decrease. We were able to corroborate our theory with measured transport data and confirm that negative resistance does exist."
For more than a decade, Low, Mkhoyan, and Wang have been collaborating on topological materials for next-generation electronic devices and systems—research that would not have been possible without the combination of their respective expertise in theory and computation, materials growth and characterization, and device fabrication. "Studying such an important and challenging topic requires not only inspiring vision, but also great patience and a group of dedicated team members across four disciplines, which will make it possible to transition this technology from the laboratory to industry," Wang said.