While studying phase transitions in vanadium dioxide (VO2), Mohammad Samizadeh Nikoo, a doctoral student at EPFL's Power and Wide-band-gap Electronics Research Laboratory (POWERlab), made an interesting discovery.
VO2 has an insulating phase when relaxed at room temperature, and undergoes a steep transition from insulator to metal at 68 ° C, where its lattice structure changes.
If you haven't gotten there yet (it's not your fault, I too only got around to it after reporting that it was excellent Lucius Plantone, passionate about the future and science and devoted reader of this site), I'll tell you. In summary, VO2 has volatile memory.
You lower the temperature, remove the "stress" and the material returns to its insulating state.
So what?
Samizadeh Nikoo was trying to find out, for his doctoral thesis, how long it took vanadium dioxide to change from one state to another. But after hundreds of measurements taken, the researcher realized that the memory of VO2 is not as volatile as it initially seemed.
The material, in fact, is able to "remember" the most recent stimulus received for up to 3 hours.
A fortunate circumstance
How many times have we commented on great discoveries born on fortuitous occasions? A cliché. Yet, even in this case it went like this.
In his experiments, Samizadeh Nikoo applied an electric current to a sample of vanadium dioxide. “The current moved through the material, following a path until it came out the other side,” he explains. By heating the sample, the current caused a change in state of VO2. Once the current passed, the material returned to its initial state.
By applying a second pulse of current to the material, the time it took to change state changed. More: it was directly linked to the 'history' of the material.
“VO2 seemed to 'remember' the first phase transition and anticipate the next one,” explains Prof. Elison Matioli, who heads EPFL's POWERlab. “We didn't expect to see this type of memory effect, which has nothing to do with electronic states but with the physical structure of the material. And it is an unprecedented discovery: no other material in the world behaves in this way."
The memory of vanadium dioxide and the consequences for computing
After the great little “Eureka” by Samizadeh Nikoo, the research was taken over by the entire laboratory, which produced a study (I link it here).
And it's just the beginning, too: The memory effect of vanadium dioxide could last for several days, Matioli says. “But at the moment we don't have the tools necessary to measure it.”
What can I say: it's a sensational thing for theinformatics. This is really important, precisely because the observed memory effect is an innate property of the material.
Using a material such as vanadium dioxide will allow for more memory capacity, more speed and more miniaturization.
And that's not all: it will allow you to store data in a completely different form from the current one (binary data that depend on the manipulation of electronic states). VO2 can actually reproduce the dynamics of human neurons.
Where will this discovery lead us?
