Cornell University researchers recently stretched individual molecules and watched electrons flow through them, proving that single-molecule devices can be used as powerful new tools for nanoscale science experiments.
The finding, reported in the June 11 issue of the journal Science, probes the effects of strong electron interactions that can be important when shrinking electronics to their ultimate small size limit--single-molecule devices. The work resulted in the first precision tests of a phenomenon known as the underscreened Kondo effect.
"The main advance in our work is that we show single-molecule devices can be very useful as scientific tools to study an interesting phenomenon that has never before been experimentally accessible," said Dan Ralph, the Cornell physics professor who led the study.
The research was funded in part by the Cornell Center for Materials Research, which is supported by the National Science Foundation's (NSF) Division of Materials Research. NSF's Division of Chemistry also contributed to the project.
"Single-molecule devices can indeed be used as model systems for making detailed quantitative studies of fundamental physics inaccessible by any other technique," said first author Joshua Parks, a postdoctoral associate in Cornell's Department of Chemistry and Chemical Biology.
Using a cobalt-based complex cooled to extremely low temperatures, Ralph, Parks and an international team of researchers watched electrons move through single molecules and accomplished a feat that until now escaped chemists and physicists. They were able to study the resistance of the flow of electricity within a system's electric field as the temperature approaches absolute zero.
This is known as the Kondo effect.
In physics, the Kondo effect is perhaps the most important model for understanding how electrons interact within a system such as a molecule. Because of the Kondo effect, when a s
|Contact: Bobbie Mixon|
National Science Foundation