The world’s smallest superconductor has been discovered by a team of scientists at Ohio University. Their study found that a sheet of four pairs of molecules superconducts at a temperature of 10K. Using synthesized molecules of a type of organic salt, (BETS)2-GaC14, placed on a surface of silver, researchers were able to observe the phenomenon in a molecular chain measuring less than 1 nanometer wide. The findings suggest that superconductivity is not limited to the macroscopic scale; it also exists at the molecular scale.
“Nobody has deposited these organic salts on a materials substrate in a clean environment before,” said Dr. Saw-Wai Hla, lead author of the paper and associate professor of physics and astronomy at Ohio University’s Nanoscale and Quantum Phenomena Institute. “These are the first scanning tunneling microscopy images of this organic salt ever published.”
A scanning tunneling microscope (STM) uses a sharp metallic tip to sense the atomic structures on a given surface. The tip scans at a height of only 1 nanometer from the surface to produce an image. Hla and his team used a home-designed low temperature STM system that operates in an ultrahigh vacuum environment. The STM scanner was cooled with liquid helium through direct thermal contact with a bath-cryostat.
According to Hla, the study opens up a new way to understand the phenomenon of superconductivity, which could lead to new materials that could be engineered to work at higher temperatures. But he says it’s hard to predict when these materials will be discovered and made available.
“We still need to search for superconducting molecular wires that operate at high temperatures,” he said.
Hla’s team began working on the project in 2007 with funding from the US Department of Energy. The findings were published as an advanced online publication in the journal Nature Nanotechnology.
Follow this link to read the story from Ohio University: http://www.ohio.edu/research/communications/index.cfm
