Navigation Links
Stretching molecules yields new understanding of electricity
Date:6/10/2010

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
bmixon@nsf.gov
703-292-8485
National Science Foundation
Source:Eurekalert

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:
*Name:
*Comment:
*Email:
(Date:2/11/2016)... , Feb. 11, 2016  Vigilant Solutions announces today that ... are being used by Lee,s Summit ... recent location and arrest of a homicide suspect. ... covers around 65 square miles and is home to ... Department has a single mobile license plate reader system and ...
(Date:2/5/2016)... 2016 http://www.researchandmarkets.com/research/5kvw8m/global_facial ) ... "Global Facial Recognition Market 2016-2020" report ... ) has announced the addition of the ... report to their offering. --> ... announced the addition of the "Global ...
(Date:2/3/2016)... http://www.researchandmarkets.com/research/d8zjcd/emotion_detection ) ... "Emotion Detection and Recognition Market by Technology ... Tools (Facial Expression, Voice Recognition and Others), ... Global forecast to 2020" report to ... ) has announced the addition of the ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... WASHINGTON , Feb. 11, 2016   BioInformant ... strategic report, "Stem Cell Research Products, Opportunities, Tools, and ... 2020. ... specialize in the stem cell industry, BioInformant has more ... of the stem cell market, by stem cell type. ...
(Date:2/11/2016)... , ... February 11, 2016 , ... ... its new stem cell treatment clinic in Quito, Ecuador. The new facility will ... trauma applications to patients from around the world. , The new GSCG ...
(Date:2/10/2016)... 10, 2016  The Maryland House of Delegates and ... that University of Maryland School of Medicine Dean ... of Maryland Medical System President and CEO Robert ... the highest honor given to the public by the ... Dean Reece and Mr. Chrencik for their contributions ...
(Date:2/10/2016)... York, and New York, New York (PRWEB) , ... ... ... Regeneron Pharmaceuticals Inc. (NASDAQ: REGN) today announced that it has ... develop new vaccines and immunotherapies for infectious diseases and cancer. , ...
Breaking Biology Technology: