Scientists have verified a 53-year-old theory on ferroelectric metals that could spawn a new class of multifunctional devices, a new study reports.
In 1965, Philip W. Anderson, a Princeton University physicist, theorized that ferroelectric metals could conduct electricity despite not existing in nature.
For decades, scientists thought it would be impossible to prove the theory. It was like trying to blend fire and water, they said. But now, Jak Chakhalian, professor of experimental physics, and colleagues at Rutgers University–New Brunswick, have succeeded. “It’s exciting,” he says.
“We created a new class of two-dimensional artificial materials with ferroelectric-like properties at room temperature that don’t exist in nature yet can conduct electricity. It’s an important link between a theory and an experiment.”
Ferroelectric materials are used in electronics such as cell phone and other antennas, computer storage, medical equipment, high precision motors, ultra-sensitive sensors, and sonar equipment. None of their materials conducts electricity.
“Ferroelectrics are a very important class of materials technologically,” he says. “They move, shrink, and expand when electricity is applied and that allows you to move things with exquisite precision. Moreover, every modern cell phone has tens of components with properties similar to ferroelectric material.”
Chakhalian couldn’t find a law of physics that says ferroelectric metals couldn’t be created, so his team used state-of-the-art tools to create sheets of materials only a few atoms thick. It’s like making sandwiches, Chakhalian says.
“When a material becomes ferroelectric, its atoms shift permanently and we wanted to add metallic properties to an artificial crystal that conducts electricity,” he says. “So we took two very thin layers to create a two-dimensional metal at the interface and added a third layer with special properties to shift the atoms in that metallic layer, creating a ferroelectric-like metal. The new structure has several functionalities built-in, and this is a big win-win.”
Yanwei Cao, a former doctoral student at Rutgers, who is now a professor at the Chinese Academy of Sciences, is the paper’s lead author. The findings appear in Nature Communications.
Source; Rutgers University