Scientists identify compound with memory: ScienceAlert

It is not alive, and has no structures approaching the complexity of the brain, but a compound called vanadium dioxide is able to ‘remember’ previous external stimuli, researchers have found.

This is the first time this capability has been identified in the material; But it may not be the last. The discovery has some very interesting implications for the development of electronic devices, particularly in data processing and storage.

“Here we report electronically accessible long-lived conformational states in vanadium dioxide that can provide a scheme for data storage and processing,” a team of researchers led by electrical engineer Mohammad Samizadeh Nikou of Ecole Polytechnique Fédérale de Lausanne in Switzerland writes in their paper.

“These glass-like functional devices can overcome traditional metal-oxide-semiconductor electronics in terms of speed, power consumption and miniaturization, as well as pave the way for neuromorphic computing and multilayer memories.”

Vanadium dioxide (VO2) is a material that has recently been floated as an alternative, or complement, to silicon as a basis for electronic devices, due to its potential to outperform the latter material as a semiconductor.

One of the most interesting properties of VO2 That is, below 68 °C (154.4 °F), it behaves as an insulator – but above that critical temperature, it suddenly switches to a metal, with better conductivity, called the metal-insulator transition.

It was only recently, in 2018, that scientists discovered why: As temperatures rise, the way atoms arrange themselves in their lattice patterns changes.

When the temperature drops again, the material returns to its original insulator state. Samizadeh Niku originally began researching how long VO had been2 Takes the transition from insulator to metal, and vice versa, he takes measurements when the switch is triggered.

These measurements revealed something very strange. However it returned to the same starting state, VO2 acted like remembered Current activity.

The experiments introduced an electric current into the material, which took a precise path from one end to the other. This current heated the VO2, causing it to change its state – the aforementioned rearrangement of the atomic structure. When the current was removed, the molecular structure relaxed again.

When the current was applied again, things got interesting.

“VO2 The transition from the first stage seemed to ‘remember’ and expect the next,” explains Alison Mattioli, an electrical engineer at EPFL. “We did not expect to see this kind of memory effect, and it has nothing to do with the electronic states but with it. Physical structure of the material. This is a novel discovery: no other material behaves this way.”

The work of the team revealed that V.O2 Some type of information stored in the currently applied current for at least three hours. It could, in fact, be significantly longer—”but we don’t currently have the tools to measure that,” Mattioli says.

The switch is reminiscent of the behavior of neurons in the brain, which serve as memory and processing units. Described as neuromorphic technology, computing based on parallel systems can have real advantages over classical chips and circuit boards.

Because this dual property is inherent in the material, VO2 All the wish list boxes for memory devices seem to be ticked: high capacity, high speed, and the possibility of scalability. Additionally, its properties give it an edge over memory devices that encode data in a binary format controlled by electrical conditions.

“We have reported glass-like dynamics in VO2 which can be excited on sub-nanosecond timescales and monitored for several orders of magnitude of time from microseconds to hours,” the researchers write.

“Our functional devices can potentially meet the continuing demands of electronics in terms of downscaling, faster operation and reduced voltage-supply levels.”

Research has been published in Nature Electronics.

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