Researchers have captured images of electronic switches functioning in a quantum device for the first time, potentially advancing the next generation of computing.
The study, conducted by scientists from the Department of Energy’s SLAC National Accelerator Laboratory, Stanford University, Hewlett Packard Labs, Penn State University, and Purdue University, has obtained the first snapshot images of crucial electronic switches operating in a quantum electronic device. Additionally, the team identified a short-lived state inside the electronic switches that, if enhanced, could aid in designing faster and more energy-efficient computers.
Millions of minuscule electronic switches are contained in electronic circuits that store and compute information, with the electronic switches vitally controlling the flow of electric current; a more comprehensive understanding of this process could help to push the boundaries of modern computing.
Xijie Wang, a SLAC scientist and collaborator, said: “This research is a breakthrough in ultrafast technology and science. It marks the first time that researchers used ultrafast electron diffraction, which can detect tiny atomic movements in a material by scattering a powerful beam of electrons off a sample, to observe an electronic device as it operates.”
Capturing the electronic switches
The team specially designed miniature electronic switches out of vanadium dioxide to conduct their investigation, a prototypical quantum material able to oscillate back and forth between insulating and electrically conducting states near room temperature and may be utilised for future ultrafast electronic switches in computers. The material also has applications in brain-inspired computing due to its ability to emit electronic pulses that are similar to the neural impulses observed in the human brain.
The team employed electrical pulses to alternate the electronic switches from a state of insulating to conducting while capturing images that highlighted the subtle changes in the arrangement of their atoms over billionths of a second. The images were attained with SLAC’s ultrafast electron diffraction camera – called MeV-UED – which were then amalgamated to form a molecular movie of the atomic motions.
Aaron Lindenberg, an investigator with the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC and a professor in the Department of Materials Science and Engineering at Stanford University, said: “This ultrafast camera can actually look inside a material and take snapshots of how its atoms move in response to a sharp pulse of electrical excitation. At the same time, it also measures how the electronic properties of that material change over time.”
By employing this state-of-the-art camera, the researchers discovered a novel, intermediate state in the material produced when the material reacts to an electric pulse by switching states from insulating to conducting.
“The insulating and conducting states have slightly different atomic arrangements, and it usually takes energy to go from one to the other,” said SLAC scientist and collaborator Xiaozhe Shen. “But, when the transition takes place through this intermediate state, the switch can take place without any changes to the atomic arrangement.”
Designing next-gen technology
The intermediate state only exists for a few millionths of a second but stabilises due to defects in the material; the researchers are now investigating how to manufacture these defects in materials to make the state more stable and longer-lasting. These advancements would enable them to create devices in which electronic switches can function without any atomic motion, resulting in higher speeds and less energy consumption.
“The results demonstrate the robustness of the electrical switching over millions of cycles and identify possible limits to the switching speeds of such devices,” said collaborator Shriram Ramanathan, a professor at Purdue. “The research provides invaluable data on microscopic phenomena that occur during device operations, which is crucial for designing circuit models in the future.”
Furthermore, the investigation has devised a new method of synthesising materials that do not exist under natural conditions, allowing scientists to observe them on ultrafast timescales and enhance their properties.
Aditya Sood, the lead author of the study and SIMES researchers, said: “This method gives us a new way of watching devices as they function, opening a window to look at how the atoms move. It is exciting to bring together ideas from the traditionally distinct fields of electrical engineering and ultrafast science. Our approach will enable the creation of next-generation electronic devices that can meet the world’s growing needs for data-intensive, intelligent computing.”
