Chameleon-like material attached to boron is close to imitating brain cells
In a new study, Texas A&M researchers in the Department of Materials Science and Engineering describe new material that approaches how brain cells mimic calculations.
Every time we wake up, our brain processes a massive amount of data to make sense of the outside world. By mimicking the way the human brain solves everyday problems, neuromorphic systems have tremendous potential to revolutionize the problem of discovering big data analysis and models that are struggling with current digital technologies.
But for artificial systems to be similar to the brain, nerve cells must repeat how they communicate at their terminals, called synapses.
In a study published in Journal of the American Chemical Society, Researchers at Texas A&M University have described a new material that captures a pattern of electrical activity at the synapse. Just as nerve cells generate an oscillating current pulse, depending on the electrical activity at the synapse, the researchers said the material rises from metal to insulator at the transition temperature decided by the device’s thermal history.
Materials are generally classified into metals or insulators, depending on how they conduct heat and electricity. But some materials, such as vanadium dioxide, have a double life. At certain temperatures, vanadium dioxide acts as an insulator, resisting the flow of heat and electric currents. But when heated to 67 degrees Celsius, vanadium dioxide undergoes a chameleon-like change in its internal properties, turning it into a metal.
These temperature-induced oscillations make vanadium dioxide an ideal candidate for brain-inspired electronic systems, as neurons also generate an oscillating current, called a potential action.
But neurons unite their inputs at their synapse. This integration continuously increases the membrane tension of the neuron, approaching a threshold value. When this section is exceeded, the neurons trigger a potential action.
“A neuron remembers the voltage of its membrane and depending on where the membrane voltage is on the threshold, the neuron will ignite or fall asleep,” said Sarbajit Banerjee, a professor in the Department of Materials Science and Engineering and a senior author of the Department of Chemistry and research. “We wanted to adjust the property of vanadium dioxide to preserve the memory of how close it is to the transition temperature so that we can begin to mimic what is happening at the synapse of biological neurons.”
The transition temperatures of a particular material are usually fixed, if there is no impurity, called dopant, unless it is added. Although a dopant can move the transition temperature depending on the type and concentration of vanadium dioxide, Banerjeek and his team aimed to achieve a way to tune the transition temperature up or down, not just the dopant concentration, but the time elapsed since it was reset. This flexibility, they found, was only possible when they used boron.
When researchers added boron to vanadium dioxide, the material passed from an insulator to a metal, but the transition temperature now depended on what was in the new metastable state created by boron.
“Biological neurons have a memory of their membrane tension; similarly, boron-nailed vanadium dioxide has a memory of its thermal history, or formally speaking, how long it has been in a metastable state, “said Diane Sellers, one of the first authors of the study and a former scientist at Banerjee Laboratory. specifies the transition temperature for transition to insulation. “
Although their system is an initial step in mimicking a biological synapse, experiments are now underway to introduce more dynamism into the behavior of the material, controlling the kinetics of the relaxation process of vanadium dioxide, said Patrick Shamberger, professor of materials science.
In the near future, Xiaofeng Qiang, a professor in the materials science department and a collaborator on this Banerjee project, plans to expand his current research by studying the atomic and electronic structures of more complex vanadium oxide compounds. In addition, the collaborative team will also investigate the possibility of creating other neuromorphic materials with alternative dopants.
“We would like to investigate whether the phenomenon we have seen with vanadium dioxide applies to other host networks and other guest atoms,” said Raymundo Arróyave, a professor in the materials science department and author of the research. “This approach can provide us with several tools to further tune the properties of these types of neuromorphic materials into different applications.”
Reference: “Hourglass and Atomic Thermometer based on the Diffusion of a Mobile Doping VOn2”Diane G. Sellers, Erick J. Braham, Ruben Villarreal, Baiyu Zhang, Abhishek Parija, Timothy D. Brown, Theodore EG Alivio, Heidi Clarke, Luis R. De Jesus, Lucia Zuin, David Prendergast, Xiaofeng Qian, Raymundo Arroyave, Patrick J. Shamberger and Sarbajit Banerjee, August 12, 2020, Journal of the American Chemical Society.
DOI: 10.1021 / jacs.0c07152
Erick J. Braham of the Department of Chemistry is the first author of this paper. Other contributors to this research are Baiyu Zhang, Timothy D. Brown, and Heidi Clarke of the materials science department; J. Mike Walker ’66 Ruben Villarreal of the Department of Mechanical Engineering; Abhish Parija, Theodore EG Alivio and Luis R. De Jesus of the Department of Chemistry; Lucia Zuin of the University of Saskatchewan, Canada; and David Prendergast Lawrence of Berkeley National Laboratory, California.
This research is funded by the National Science Foundation and the Air Force Office of Scientific Research.