Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Stretching single molecules allows precision studies of interacting electrons

A scanning electron micrograph of a gold bridge suspended 40 nanometers above a silicon substrate. In the experiment, the bridge is severed in the middle, a single molecule is suspended across the gap, and the substrate is bent to stretch the molecule while simultaneously measuring the electron current through the molecule. Credit: Joshua Parks
A scanning electron micrograph of a gold bridge suspended 40 nanometers above a silicon substrate. In the experiment, the bridge is severed in the middle, a single molecule is suspended across the gap, and the substrate is bent to stretch the molecule while simultaneously measuring the electron current through the molecule. Credit: Joshua Parks

Abstract:
Scientists everywhere are trying to study the electrical properties of single molecules. With controlled stretching of such molecules, Cornell researchers have demonstrated that single-molecule devices can serve as powerful new tools for fundamental science experiments. Their work has resulted in detailed tests of long-existing theories on how electrons interact at the nanoscale.

By Anne Ju

Stretching single molecules allows precision studies of interacting electrons

Ithaca, NY | Posted on June 11th, 2010

The work, led by professor of physics Dan Ralph, is published in the June 10 online edition of the journal Science. First author is Joshua Parks, a former graduate student in Ralph's lab.

The scientists studied particular cobalt-based molecules with so-called intrinsic spin -- a quantized amount of angular momentum. Theories first postulated in the 1980s predicted that molecular spin would alter the interaction between electrons in the molecule and conduction electrons surrounding it, and that this interaction would determine how easily electrons flow through the molecule. Before now, these theories had not been tested in detail because of the difficulties involved in making devices with controlled spins.

Understanding single-molecule electronics requires expertise in both chemistry and physics, and Cornell's team has specialists in both.

"People know about high-spin molecules, but no one has been able to bring together the chemistry and physics to make controlled contact with these high-spin molecules," Ralph said.

The researchers made their observations by stretching individual spin-containing molecules between two electrodes and analyzing their electrical properties. They watched electrons flow through the cobalt complex, cooled to extremely low temperatures, while slowly pulling on the ends to stretch it. At a particular point, it became more difficult to pass current through the molecule. The researchers had subtly changed the magnetic properties of the molecule by making it less symmetric.

After releasing the tension, the molecule returned to its original shape and began passing current more easily -- thus showing the molecule had not been harmed. Measurements as a function of temperature, magnetic field and the extent of stretching gave the team new insights into exactly what is the influence of molecular spin on the electron interactions and electron flow.

The effects of high spin on the electrical properties of nanoscale devices were entirely theoretical issues before the Cornell work, Ralph said. By making devices containing individual high-spin molecules and using stretching to control the spin, the Cornell team proved that such devices can serve as a powerful laboratory for addressing these fundamental scientific questions.

The study was funded primarily by the National Science Foundation through the Cornell Center for Materials Research, a Materials Research Science and Engineering Center.

####

For more information, please click here

Contacts:
Media Contact:
Blaine Friedlander
(607) 254-8093


Cornell Chronicle:
Anne Ju
(607) 255-9735


Related Information:
Dan Ralph group people.ccmr.cornell.edu/~ralph/

Copyright © Cornell University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Antibacterial Ceramic Nanoparticles, Appropriate Material for Medical Devices May 3rd, 2015

Oxford Instruments announces winners of the 2015 Sir Martin Wood Science Prize for China May 2nd, 2015

Time Dependant Spectroscopy of Microscopic Samples: CRAIC TimePro™ software is used with CRAIC Technologies microspectrometers to measure the kinetic UV-visible-NIR, Raman and fluorescence spectra of microscopic sample areas May 2nd, 2015

ORNL researchers probe chemistry, topography and mechanics with one instrument May 2nd, 2015

Physics

Oxford Instruments announces winners of the 2015 Sir Martin Wood Science Prize for China May 2nd, 2015

Chemistry

Chemists strike nano-gold: 4 new atomic structures for gold nanoparticle clusters: Research builds upon work by Nobel Prize-winning team from Stanford University April 28th, 2015

Scientists join forces to reveal the mass and shape of single molecules April 27th, 2015

Cacao Seed Extract Used in Production of Catalytic Nanoparticles April 27th, 2015

Scientists Use Nanoscale Building Blocks and DNA 'Glue' to Shape 3D Superlattices: New approach to designing ordered composite materials for possible energy applications April 23rd, 2015

Govt.-Legislation/Regulation/Funding/Policy

ORNL researchers probe chemistry, topography and mechanics with one instrument May 2nd, 2015

Making robots more human April 29th, 2015

Artificial photosynthesis could help make fuels, plastics and medicine April 29th, 2015

Research seeks alternatives for reducing bacteria in fresh produce using nanoengineering April 29th, 2015

Academic/Education

FEI Partners With the George Washington University to Equip New Science & Engineering Hall: Suite of new high-performance microscopes will be used for cutting-edge experiments at GW’s new research facility April 29th, 2015

Renishaw Raman systems used to study 2D materials at Boston University, Massachusetts, USA. April 28th, 2015

SUNY Poly and Sematech Announce Air Products Joins Cutting-Edge CMP Center At Albany Nanotech Complex April 28th, 2015

SEFCU, SUNY Poly CNSE Announce Winning Student-Led Teams in the 6th Annual $500,000 New York Business Plan Competition April 25th, 2015

Announcements

Antibacterial Ceramic Nanoparticles, Appropriate Material for Medical Devices May 3rd, 2015

Nanometrics to Present at the B. Riley & Co. 16th Annual Investor Conference May 2nd, 2015

Time Dependant Spectroscopy of Microscopic Samples: CRAIC TimePro™ software is used with CRAIC Technologies microspectrometers to measure the kinetic UV-visible-NIR, Raman and fluorescence spectra of microscopic sample areas May 2nd, 2015

ORNL researchers probe chemistry, topography and mechanics with one instrument May 2nd, 2015

Quantum nanoscience

Quantum particles at play: Game theory elucidates the collective behavior of bosons April 29th, 2015

When mediated by superconductivity, light pushes matter million times more April 28th, 2015

More is less in novel electronic material: Adding electrons actually shrinks the system April 27th, 2015

Quantum 'paparazzi' film photons in the act of pairing up April 22nd, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project