Adding layers of molybdenum sulfide to molybdenum carbide allows superconductivity to occur at 50% higher temperatures. Image: Elizabeth Flores-Gomez Murray/Penn State.The possibility of achieving room temperature superconductivity took a tiny step forward with a recent discovery by a team of physicists and materials scientists at Penn State. Their surprising discovery involved layering a 2D material called molybdenum sulfide with another material called molybdenum carbide.
Molybdenum carbide is a known superconductor – electrons can flow through the material without any resistance. Even the best of metals, such as silver or copper, lose energy through heat. This loss makes long-distance transmission of electricity more costly.
"Superconductivity occurs at very low temperatures, close to absolute zero or 0 Kelvin," said Mauricio Terrones, corresponding author of a paper on this work in the Proceedings of the National Academy of Sciences. "The alpha phase of Moly carbide is superconducting at 4 Kelvin."
However, the researchers found that when they layered metastable phases of molybdenum carbide with molybdenum sulfide, superconductivity started to occur at 6 Kelvin, a 50% increase in temperature. Although this is not remarkable in itself – other materials have been shown to be superconducting at temperatures as high as 150 Kelvin – it was still an unexpected phenomenon that portends a new method for increasing superconductivity temperatures in other superconducting materials.
The researchers used modeling techniques to understand how the effect occurred.
"Calculations using quantum mechanics as implemented within density functional theory assisted in the interpretation of experimental measurements to determine the structure of the buried molybdenum carbide/molybdenum sulfide interfaces," said Susan Sinnott, professor of materials science and engineering and head of the department at Penn State. "This work is a nice example of the way in which materials synthesis, characterization and modeling can come together to advance the discovery of new material systems with unique properties."
"It's a fundamental discovery, but not one anyone believed would work," added Terrones. "We are observing a phenomenon that to the best of our knowledge has never been observed before."
The team will continue experimenting with superconducting materials, with the goal of someday finding material combinations that can carry energy through the electricity grid with zero resistance.
This story is adapted from material from Penn State, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.