Brain-Like Supercomputers: Harnessing Charge Density Waves for Revolutionary Efficiency

Physics Waves Electronic Circuits Art Concept Illustration — Researchers are advancing energy-efficient supercomputing by harnessing charge density waves in materials, a technique that mimics brain neurons. New microscopy methods at Argonne National Laboratory are revealing how these waves can be manipulated through electricity, offering insights into faster, smaller, and more efficient microelectronic devices. Credit: SciTechDaily.com

Charge density waves have applications in next-generation and energy-efficient computing.

Scientists used an ultrafast electron microscope to capture the nanosecond changes in a material during electrical pulsing. Understanding these changes may lead to more energy-efficient electronics.

Today’s supercomputers consume vast amounts of energy, equivalent to the power usage of thousands of homes. In response, researchers are developing a more energy-efficient form of next-generation supercomputing that leverages artificial neural networks. These networks mimic the processes of neurons, the basic unit in the human brain. This mimicry could be achieved through the charge density waves that occur in certain materials. Charge density waves are wave-like patterns of electrons — negatively charged particles — that move in a correlated fashion.

Unraveling the Dynamics of Charge Density Waves

The charge density waves increase the resistance to the movement of electrons in the material. The ability to control the waves could provide fast switching of the resistance on and off. This property could then be exploited for more energy-efficient computing, as well as ultraprecise sensing. However, it is not clear how the switching process occurs, especially given that the waves change from one state to another within 20 billionths of a second.

“This new technique produced results with broad applications to energy-efficient microelectronics.”

Charudatta Phatak, materials scientist and deputy division director

Advancements in Microscopy at Argonne National Laboratory

Researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have found a new way to study these waves. To do so, they turned to the ultrafast electron microscope at the Center for Nanoscale Materials, a DOE Office of Science user facility at Argonne. They developed a new microscopy technique that uses electrical pulses to observe the nanosecond dynamics within a material that is known to form charge density waves at room temperature. That material is a tantalum sulfide referred to as 1T-TaS₂.

The team tested a flake of this sulfide with two electrodes attached to generate electric pulses. During short pulses it was thought that the resulting high electric field or currents might drive the resistance switching. But two observations from the ultrafast electron microscope changed this understanding.

Diffraction Patterns Electrical Pulse — Diffraction patterns captured before and after a 20-nanosecond electrical pulse. The star-shaped pattern of small white spots, left, corresponds to the initial charge density wave pattern, which is temporarily melted by the heat from electrical pulse, right. Credit: Argonne National Laboratory

First, the charge density waves melted in response to the heat generated by the injected current rather than the charge current itself, even during nanosecond pulses. Second, the electrical pulses induced drum-like vibrations across the material, which wobbled the waves’ arrangement.

“Thanks to this new technique we determined these two previously unobserved ways in which electricity can manipulate the state of the charge density waves,” said Daniel Durham, a postdoctoral researcher at Argonne. “And the melting response mimics how neurons are activated in the brain, while the vibrational response could generate neuron-like firing signals in a neural network.”

This study demonstrates a new approach to examining these types of electrical switching processes. This ultrafast electron microscopy method allows researchers to observe how microelectronic materials function at <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

nanoscale

The term "nanoscale" refers to dimensions that are measured in nanometers (nm), with one nanometer equaling one-billionth of a meter. This scale encompasses sizes from approximately 1 to 100 nanometers, where unique physical, chemical, and biological properties emerge that are not present in bulk materials. At the nanoscale, materials exhibit phenomena such as quantum effects and increased surface area to volume ratios, which can significantly alter their optical, electrical, and magnetic behaviors. These characteristics make nanoscale materials highly valuable for a wide range of applications, including electronics, medicine, and materials science.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>nanoscale lengths and nanosecond speeds.

The drive toward smaller, faster, and more efficient microelectronic devices makes a material like 1T-TaS₂ attractive. And its ability to be formed as a nanoscale layer also makes it appealing for such devices.

This new technique produced results with broad applications to energy-efficient microelectronics, according to Charudatta Phatak, a materials scientist and deputy division director at Argonne.

“Understanding the fundamental mechanisms of how we can control these charge density waves is important because this can be applied to other materials to control their properties,” Phatak said.

This research was published in <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

Physical Review Letters

<em>Physical Review Letters (PRL)</em> is a prestigious peer-reviewed scientific journal published by the American Physical Society. Launched in 1958, it is renowned for its swift publication of short reports on significant fundamental research in all fields of physics. PRL serves as a venue for researchers to quickly share groundbreaking and innovative findings that can potentially shift or enhance understanding in areas such as particle physics, quantum mechanics, relativity, and condensed matter physics. The journal is highly regarded in the scientific community for its rigorous peer review process and its focus on high-impact papers that often provide foundational insights within the field of physics.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>Physical Review Letters.

Reference: “Nanosecond Structural Dynamics during Electrical Melting of Charge Density Waves in 1T−TaS₂” by Daniel B. Durham, Thomas E. Gage, Connor P. Horn, Xuedan Ma, Haihua Liu, Ilke Arslan, Supratik Guha and Charudatta Phatak, 28 May 2024, Physical Review Letters.
DOI: 10.1103/PhysRevLett.132.226201

Besides Durham and Phatak, authors include Thomas Gage, Connor Horn, Xuedan Ma, Haihua Liu, Ilke Arslan and Supratik Guha. Horn and Guha have joint appointments at the <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

University of Chicago

Founded in 1890, the University of Chicago (UChicago, U of C, or Chicago) is a private research university in Chicago, Illinois. Located on a 217-acre campus in Chicago's Hyde Park neighborhood, near Lake Michigan, the school holds top-ten positions in various national and international rankings. UChicago is also well known for its professional schools: Pritzker School of Medicine, Booth School of Business, Law School, School of Social Service Administration, Harris School of Public Policy Studies, Divinity School and the Graham School of Continuing Liberal and Professional Studies, and Pritzker School of Molecular Engineering.

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>University of Chicago.

This work was supported by the DOE Office of Science call for microelectronics research.