BOSTON (Northeastern University) -- Researchers at Northeastern University have discovered how to change the electronic state of matter on demand, a breakthrough that could make electronics 1,000 times faster and more efficient.
By switching from insulating to conducting and vice versa, the discovery creates the potential to replace silicon components in electronics with exponentially smaller and faster quantum materials.
“Processors work in gigahertz right now,” said Alberto de la Torre, assistant professor of physics and lead author of the research. “The speed of change that this would enable would allow you to go to terahertz.”
Via controlled heating and cooling, a technique they call “thermal quenching,” researchers are able to make a quantum material switch between a metal conductive state and an insulating state. These states can be reversed instantly using the same technique.
Published in the journal Nature Physics, the research findings represent a breakthrough for materials scientists and the future of electronics: instant control over whether a material conducts or insulates electricity.
The effect is like a transistor switching electronic signals. And just as transistors allowed computers to become smaller—from the huge machines the size of rooms to the phone in your pocket—control over quantum materials has the potential to transform electronics, says Gregory Fiete, a professor of physics at Northeastern who worked with de la Torre to interpret the findings.
“Everyone who has ever used a computer encounters a point where they wish something would load faster,” says Fiete. “There’s nothing faster than light, and we’re using light to control material properties at essentially the fastest possible speed that’s allowed by physics.”
By shining light on a quantum material called 1T-TaS₂ at close to room temperature, researchers achieved a “hidden metallic state” that had so far only been stable at cryogenically cold temperatures. Now researchers have created that conductive metallic state at more practical temperatures, says de la Torre. The material maintains its programmed state for months—something that has never been accomplished before.
“One of the grand challenges is, how do you control material properties at will?” says Fiete. “What we’re shooting for is the highest level of control over material properties. We want it to do something very fast, with a very certain outcome, because that’s the sort of thing that can be then exploited in a device.”
So far, electronic devices have needed both conductive and insulating materials, plus a well-engineered interface between the two. This discovery makes it possible to use just one material that can be controlled with light to conduct and then insulate.
“We eliminate one of the engineering challenges by putting it all into one material,” Fiete says. “And we replace the interface with light within a wider range of temperatures.”
The research expands upon previous work that used ultra-fast laser pulses to temporarily change the way materials conduct electricity. But those changes only lasted tiny fractions of a second and usually at extremely cold temperatures.
Stable conductivity switching at higher temperatures is a significant advance for quantum mechanics, Fiete says, and for the long game of supplementing or replacing silicon-based technology. Semiconductors, he says, are so dense with logic components that engineers are now stacking them in three dimensions. But this approach has limitations, he said, which make tiny quantum materials more important for electronics design.
“We’re at a point where in order to get amazing enhancements in information storage or the speed of operation, we need a new paradigm,” Fiete says. “Quantum computing is one route for handling this and another is to innovate in materials. That’s what this work is really about.”