Navigation Links
Stretching molecules yields new understanding of electricity

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 spinning molecule is attached to electrodes, interactions between the molecule and electrons lead to coordinated motion of the electrons, resulting in a localized cloud of electrons that cancels out the molecule's spin and permits the electrons to flow with decreasing resistance as the temperature approaches zero degrees Kelvin, -273 degrees Fahrenheit.

However, theories since 1980 have also predicted for certain types of high-spin molecules the possibility of an underscreened Kondo effect, in which the spin of the molecule is not completely cancelled and the resulting correlations between the flowing electrons are not as complete.

The researchers tested the Kondo effect by placing the cobalt-based complex between two electrodes and slowly stretching individual spin-containing molecules. They were able to manipulate the molecule's magnetic properties and make precise tests of how electrical resistance changes with variations in temperature. The results were found to be in good agreement with predictions for the underscreened Kondo effect.

"The research shows mechanical control can be a realistic strategy for manipulating molecular spin states, to supplement or replace the use of magnetic fields in proposed applications such as quantum computing or information storage," said Parks.


Contact: Bobbie Mixon
National Science Foundation

Related biology news :

1. Scripps Research scientists break barrier to creating potential therapeutic molecules
2. New method for producing libraries of important carbohydrate molecules
3. Intracellular express -- why transport protein molecules have brakes
4. Light activated warhead turns modest molecules into super protein killers
5. New sensor array detects single molecules for the first time
6. New cancer-fighting strategy focuses on signaling molecules
7. When molecules leave tire tracks
8. Research at Marshall University may lead to new ways to transport and manipulate molecules
9. Small molecules found to protect cells in multiple models of Parkinsons disease
10. Just like old times: Generating RNA molecules in water
11. New synthetic molecules trigger immune response to HIV and prostate cancer
Post Your Comments:
(Date:6/21/2016)... 2016 NuData Security announced today that Randy ... principal product architect and that Jon Cunningham ... development. Both will report directly to Christopher ... reflect NuData,s strategic growth in its product and ... demand and customer focus values. ...
(Date:6/9/2016)... , June 9, 2016 ... Police deploy Teleste,s video security solution to ensure the safety ... France during the major tournament Teleste, ... communications systems and services, announced today that its video security ... to back up public safety across the country. ...
(Date:6/2/2016)... , June 2, 2016 Perimeter ... Platforms, Unmanned Systems, Physical Infrastructure, Support & Other Service  ... visiongain offers comprehensive analysis of the global ... market will generate revenues of $17.98 billion in 2016. ... DVTEL Inc, a leader in software and hardware technologies ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... NY (PRWEB) , ... June 24, 2016 , ... While ... machines such as the Cary 5000 and the 6000i models are higher end machines ... is the height of the spectrophotometer’s light beam from the bottom of the cuvette ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one of ... their brand, UP4™ Probiotics, into Target stores nationwide. The company, which has been ... Target to its list of well-respected retailers. This list includes such fine stores ...
(Date:6/23/2016)... SILVER SPRING, Md. , June 23, 2016 ... evidence collected from the crime scene to track the criminal ... sick, and the U.S. Food and Drug Administration (FDA) uses ... Sound far-fetched? It,s not. ... whole genome sequencing to support investigations of foodborne illnesses. Put ...
(Date:6/23/2016)... , June 23, 2016  The Prostate Cancer Foundation (PCF) ... precise treatments and faster cures for prostate cancer. Members of the Class of ... 15 countries. Read More About the Class of 2016 ... ... ...
Breaking Biology Technology: