Research into proximity ferroelectricity is revealing new materials for data storage and wireless communications, according to recent Penn State research seeking to address how AI demands are stretching computing supply chains thin.
Ferroelectric materials have a strange property whereby applying an electric current can reverse their polarization and also return them to their original state. This easy ability to switch between two states makes the materials perfect for holding the binary codes that underlie our computing infrastructure.
Proximity Ferroelectricy Demonstrated
The Penn State researchers demonstrated a proximity ferroelectricity in which a non-ferroelectric material can become ferroelectric simply by placing it against a ferroelectric material. This expansion of available materials can stretch the supply of ferroelectrics, helping meet global data storage demands.
Earlier methods for developing ferroelectricity in non-ferroelectric materials involved altering the chemical formulations. Unfortunately, those modifications can have negative side effects, degrading the material’s utility. This fresh source of unimpaired ferroelectric materials can benefit both optoelectronics and quantum computing.
“This work shows we can generate ferroelectricity in a material that does not have those properties just by stacking it with a material that is ferroelectric,” said Jon-Paul Maria, professor of materials science and engineering at Penn State and study co-author.
“And, so, it has to be that the two materials are talking to each other. We call it proximity ferroelectricity because it is an effect of being in contact.”
A History In Ferroelectric Research
Maria’s team is not new to ferroelectric research, having previously developed another material that showed some promise but also had limitations. That material was magnesium-substituted zinc oxide, which added the ferroelectric capabilities of magnesium to zinc oxide but impeded zinc oxide base heat dissipations and light transmission properties. Ferroelectricity mitigated the trade-off by stacking the two and allowing unadulterated zinc oxide to absorb magnesium-substituted zinc oxide.
According to the Penn State team, only 3% of the total volume must consist of ferroelectric material placed on the top, bottom, or middle to disperse the property effectively. This minimal requirement means that engineers can maximize the desired properties of most materials.
“Imagine that I have the ability to stack these layers on top of each other, where one is ferroelectric and the other is normally not, but through proximity ferroelectricity,” Maria said. “It can exhibit the polarization reversal in its pure state. That’s the real appeal.”
International Work on Ferroelectric Data Storage
Work has been progressing on this front internationally, with the University of Kiel scientists focused on nitride ferroelectrics and the Penn State team doing oxide ferroelectrics. These materials’ simple structures and preparation methods make them ideal for integrating with silicon and other common semiconductors. According to the Penn State team, manufacturers having the ability to pair these advances with existing technologies will maximize their impact.
“The community got very excited in the last few years about two new emergent families of ferroelectrics that show very promising future impacts on electronic devices,” Maria said. “This is now another step in that process. It’s a second time that we’ve been stunned about what we did not know about ferroelectricity after 100 years of research.”
Next Steps for Ferroelectric Data Storage
Researchers identified the proximity ferocity phenomenon in oxide, nitride, and nitride-oxide systems, indicating that an underlying mechanism produces the effect. Following up on this mechanism can advance ferroelectric engineering and material discovery. Maria suggests that future research should investigate other material combinations that can make the ferroelectric proximity effect. With optical communication a leading format for high-speed transfers, the technology could boost next-generation optics capabilities by allowing processors to talk to each other with significantly reduced energy consumption.
“And a big part of that may be this next generation of opto-electronic materials,” Maria said. “Our findings could be one candidate. Alternatively, this could mean that other enabling materials are already known, and exciting functional properties like ferroelectric switching just need unlocking using this proximity effect.”
The paper “Proximity Ferroelectricity in Wurtzite Heterostructures” appeared on January 9, 2025 in the Science.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.