Electric fields control the flow of charge in modern electronic chips, powering computers, smartphones and other devices. But as chips continue to shrink, this approach is reaching its physical limits.
Now, a team led by researchers at the UCLA Samueli School of Engineering has shown that a small electric signal could trigger a response more than 100 times larger than what is typically observed in conventional electronic materials, potentially opening a path toward smaller, more energy-efficient devices.
Published in Nature Electronics , their study revealed a new way to control electricity using a quantum-like collective state of matter known as a charge-density-wave, in which electrons move together in a synchronized pattern rather than independently.
The researchers built prototype devices just a few nanometers thick using crystals of tantalum trisulfide, a material that naturally hosts charge-density waves. By combining advanced nanofabrication techniques with radio-frequency measurements, they directly observed the collective motion of electrons and measured how strongly the electronic state responded to an applied electric field.
"Our research reveals an unexpected amplification effect that emerges when electrons act collectively rather than individually," said study co-corresponding author Alexander Balandin , the Fang Lu Professor in Engineering and a distinguished professor of materials science and engineering at UCLA Samueli. "This suggests a new strategy for controlling electricity in future devices."
Charge-density waves occur when electrons organize themselves into repeating patterns within a material, creating a collective electronic state that behaves differently from ordinary electrical conduction. While previous studies showed that electric fields can influence these states, the UCLA-led team directly measured how an electric field changes the density of collective charge within a charge-density-wave state. The researchers were also able to separate the behavior of individual electrons from the collective electronic state, something that has previously been difficult to achieve.
Although the research is still at the proof-of-concept stage, the device architecture resembles structures already used in modern silicon chips, raising the likelihood that the approach could be incorporated into current and future generations of semiconductor devices.
"The similarities suggest that the newly discovered effect may not require an entirely new technological platform," said study first author Maedeh Taheri, a postdoctoral researcher working in Balandin's lab . "It could potentially be adapted into device architectures already standard in the semiconductor industry."
Other authors include Jordan Teeter, a UCLA Samueli doctoral student and a member of Balandin's research group, and co-corresponding author Roger Lake, a professor of electrical and computer engineering at UC Riverside. Additional authors are Topojit Debnath of UC Riverside and Nicholas Sesing and Tina Salguero of the University of Georgia. Balandin is a member of the California NanoSystems Institute at UCLA and serves as a research thrust lead of UCLA Samueli's Semiconductor Hub , which launched in May.
The study was funded by the Office of Naval Research.
