Ferroelectric materials could lead to brain-like computing

Research reported in a paper in Scientific Reports lays out a theoretical map for using ferroelectric material to process information with multivalued logic. This type of logic offers a leap beyond the simple ones and zeroes used in current computing systems, allowing information to be processed much more efficiently.

The language of computers is currently written in just two symbols – ones and zeroes, representing yes or no. But a world of richer possibilities awaits us if we could expand to three or more values, so that the same physical switch could encode much more information.

"Most importantly, this novel logic unit will enable information processing using not only ‘yes’ and ‘no’, but also ‘either yes or no’ or ‘maybe’ operations," said Valerii Vinokur, a materials scientist and distinguished fellow at the US Department of Energy's Argonne National Laboratory and corresponding author on the paper. The other authors are Laurent Baudry at the Lille University of Science and Technology and Igor Lukyanchuk at the University of Picardie Jules Verne, both in France.

Multivalued logic follows the way our brains operate, and they're on the order of a million times more efficient than the best computers we've ever managed to build – while consuming orders of magnitude less energy. "Our brains process so much more information, but if our synapses were built like our current computers are the brain would not just boil but evaporate from the energy they use," Vinokur said.

While the advantages of multivalued logic have long been known, the problem is that scientists haven't discovered a material system that can implement it. Right now, transistors can only operate as ‘on’ or ‘off’, so this new system would have to find a new way to consistently maintain more states – as well as be easy to read and write and, ideally, work at room temperature.

Hence Vinokur's interest in ferroelectrics, a class of materials whose polarization can be controlled with electric fields. As ferroelectrics physically change shape when their polarization changes, they're very useful in sensors and other devices such as medical ultrasound machines. Scientists are also very interested in tapping these properties for computer memory and other applications; but the theory behind their behavior is very much still emerging.

In this new paper, Vinokur and his colleagues lay out a recipe for taking advantage of the properties of very thin films of a particular class of ferroelectric material called perovskites. According to their calculations, perovskite films could hold two, three or even four polarization positions that are energetically stable – "so they could 'click' into place, and thus provide a stable platform for encoding information," Vinokur said.

The team calculated these stable configurations and worked out how to move the polarization between stable positions with electric fields, Vinokur said. "When we realize this in a device, it will enormously increase the efficiency of memory units and processors," Vinokur said. "This offers a significant step towards realization of so-called neuromorphic computing, which strives to model the human brain."

Vinokur said the team is now working with experimentalists to apply the principles to create a working system.

This story is adapted from material from Argonne National Laboratory, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.