Researchers at the University of Minnesota Twin Cities have found a new way to change how a metal behaves electronically by controlling atomic-level interactions at the boundary where two materials meet.
The study, published in Nature Communications, shows that interfacial polarization can shift the surface work function of metallic ruthenium dioxide (RuO2) by more than 1 electron volt (eV), simply by changing film thickness at the nanometer scale.
“We often think of polarization as something that belongs to insulators or ferroelectrics—not metals,” said Bharat Jalan, professor and Shell Chair in the Department of Chemical Engineering and Materials Science at the University of Minnesota. “Our work shows that, through careful interface design, you can stabilize polarization in a metallic system and use it as a knob to tune electronic properties. This opens an entirely new way of thinking about controlling metals.”
Atomic packing changes conductivity
The effect becomes strongest when the metal film is about 4 nanometers thick, roughly the width of a single strand of DNA. At that scale, the metal changes from a “stretched” arrangement imposed by the underlying material to a more “relaxed” structure. That shift shows that the way atoms are physically arranged can directly and measurably influence how a metal conducts and responds to electricity.
“This was surprising,” said Seung Gyo Jeong, first author of the study and a researcher in Jalan’s group. “We expected subtle interface effects, but not such a large and controllable change in work function. Being able to visualize the polar displacements at the atomic scale and connect them directly to electronic measurements was especially exciting.”
The discovery goes beyond basic physics and could help guide the development of future electronic, catalytic, and quantum devices.
The research was funded by the U.S. Department of Energy and the Air Force Office of Scientific Research.
By – https://scitechdaily.com/scientists-discover-a-new-way-to-control-metals-at-the-atomic-scale/