Ultra-fast snapshots of transitions in quantum electronics could lead to faster computing devices

Researchers capture first snapshots of ultrafast switching in a quantum electronic device

They discover a near-term condition that could lead to faster and more energy-efficient computing equipment.

The electronic circuits that compute and store information contain millions of tiny switches that control the flow of electric current. A better understanding of how these tiny switches work could help researchers push the boundaries of modern computers.

Now scientists have captured the first shots of atoms moving in an electric switch as it turns on and off. Among other things, they discovered a temporary state of the switch that could one day be used for faster and more energy-efficient data-processing units.

The research team from the Department of Energy’s SLAC National Accelerator Laboratory, Stanford University, Hewlett-Packard Laboratories, Pennsylvania State University, and Purdue University described their work in an article published in Science Today (July 15, 2021).

“This study is a breakthrough in ultra-fast science and technology,” said researcher and SLAC partner Xijie Wang. A powerful electron beam from the endoscope to monitor an electronic device during operation.

The team used electrical pulses, shown here in blue, to turn the assigned switches on and off multiple times. They programmed these electrical pulses to arrive before the electron pulses produced by the SLAC MeV-UED’s ultra-fast electron diffraction source, which captures the atomic motions that occur in these switches when they are turned on and off. Credit: Greg Stewart/SLAC National Accelerator Laboratory

Select the path

In this experiment, the team engineered custom-made miniature electronic switches from vanadium dioxide, a model quantum material whose ability to switch between dielectric and electrical conduction conditions near room temperature could be used as a key to future computers. The material also has applications in brain-inspired computers due to its ability to create electronic impulses that mimic nerve impulses fired in the human brain.

The scientists used electrical pulses to toggle these switches between the insulating and conducting states while capturing still images showing tiny changes in the arrangement of their atoms in a billionth of a second. These snapshots, captured with SLAC’s ultra-fast electron diffraction camera, MeV-UED, were stitched together to create a molecular film of atomic motion.

Principal investigator Aditya Sood is investigating new research that could lead to a better understanding of how small switches work in electronic circuits. Credit: Olivier Bonin/SLAC National Accelerator Laboratory

said collaborator Aaron Lindenberg, a researcher at the Stanford Institute for Materials and Energy Sciences (SIMES) in Slack. He is a professor in the Department of Materials Science and Engineering at Stanford University. “At the same time, it also measures how the electronic properties of a material change over time.”

Using this camera, the team discovered a new intermediate state in the material. It occurs when a material responds to an electrical impulse by switching from its insulating state to a conductor.

“Isolated countries and lead countries have slightly different nuclear arrangements, and it usually takes energy to switch from one to the other,” said researcher and SLAC partner Xiaozhe Shen. “But when the transition occurs through this intermediate state, the change can occur without any change in the nuclear arrangement.”

Open a window on atomic motion

Although the intermediate state is only a few millionths of a second, it stabilizes due to imperfections in the material.

To continue this research, the team is looking at how these defects can be incorporated into the material to make this new state more stable and persistent. This will allow them to create devices in which electronic circuits can occur without atomic motion, which will run faster and require less power.

“The results show the power of electrical switching over millions of cycles and define potential limits for the switching speed of such devices,” said collaborator Shriram Ramanathan, a professor at Purdue University. “The research provides invaluable data on microscopic phenomena that occur during device operations, which is critical for designing future circuit models.”

The research also offers a new way to synthesize materials not found in natural conditions, allowing scientists to track them at ultrafast timescales and then tweak their properties.

“This method gives us a new way of looking at devices in action and opens a window into how atoms move,” said SIMES author and principal investigator Aditya Sood. “It is exciting to bring together ideas from the traditionally different fields of electrical engineering and ultra-fast science. Our approach will enable the creation of next-generation electronic devices that can meet the growing global needs for intelligent, data-intensive computing.”

MeV-UED is a tool for the LCLS User Facility, which is operated by SLAC on behalf of the Department of Energy’s Office of Science, which funded this research.

SLAC is a vibrant laboratory with many programs that explore how the universe operates on the largest, smallest, and fastest scales, creating powerful tools used by scientists around the world. Through research that includes particle physics, astrophysics, cosmology, materials, chemistry, life sciences and scientific informatics, we help solve real-world problems and advance the interests of the nation.

SLAC is managed by the Stanford University Office of Science of the US Department of Energy. The Office of Science is the largest sponsor of basic science research in the United States and works to address some of the most pressing challenges of our time.