Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > New study confirms exotic electric properties of graphene

© Calvin Davidson, British Carbon Group
This illustration shows the tip of a scanning tunnelling microscope approaching an undulating sheet of perfect graphene.
© Calvin Davidson, British Carbon Group This illustration shows the tip of a scanning tunnelling microscope approaching an undulating sheet of perfect graphene.

Abstract:
First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now, the hottest new material in physics and nanotechnology is graphene: a remarkably flat molecule made of carbon atoms arranged in hexagonal rings much like molecular chicken wire.

New study confirms exotic electric properties of graphene

Nashville, TN | Posted on November 17th, 2009

Not only is this the thinnest material possible, but it also is 10 times stronger than steel and it conducts electricity better than any other known material at room temperature. These and graphene's other exotic properties have attracted the interest of physicists, who want to study them, and nanotechnologists, who want to exploit them to make novel electrical and mechanical devices.

"There are two features that make graphene exceptional," says Kirill Bolotin, who has just joined the Vanderbilt Department of Physics and Astronomy as an assistant professor. "First, its molecular structure is so resistant to defects that researchers have had to hand-make them to study what effects they have. Second, the electrons that carry electrical charge travel much faster and generally behave as if they have far less mass than they do in ordinary metals or superconductors."

Bolotin has been directly involved in the efforts to manufacture and characterize this exotic new material as a post-doctoral fellow in the laboratory of Philip Kim at Columbia University. In a paper published last week in the journal Nature, he and his Columbia colleagues report that they have managed to clean up graphene enough so that it exhibits a bizarre electrical phenomenon called the fractional quantum Hall effect, where the electrons act together to create new particles with electrical charges that are a fraction that of individual electrons.

Although graphene is the first truly two-dimensional crystalline material that has been discovered, over the years scientists have put considerable thought into how two-dimensional gases and solids should behave. They have also succeeded in creating a close approximation to a two-dimensional electron gas by bonding two slightly different semiconductors together. Electrons are confined to the interface between the two and their motions are restrained to two dimensions. When such a system is cooled down to less than one degree above absolute zero and a strong magnetic field is applied, then the fractional quantum Hall effect appears.

Since scientists figured out how to make graphene five years ago, they have been trying to get it to exhibit this effect with only marginal success. According to Bolotin, the Columbia group figured out that interference from the surface the graphene was sitting on was the problem. So they applied semiconductor lithography techniques to suspend ultraclean graphene sheets between microscopic posts above the surface of semiconductor chips. When they cooled this configuration down within six degrees of absolute zero and applied a magnetic field, the graphene generated a robust quantum Hall effect as predicted by theory.

The best way to understand this counterintuitive effect is to think of the electrons in graphene as a forming a (very thin) sea of charge. When the magnetic field is applied, it generates whirlpools in the electron fluid. Because electrons carry a negative charge, these vortices have a positive charge. They form with fractional charges such as one-third, one-half and two-thirds that of an electron. These positive charge carriers are attracted to and attach to the conduction electrons, creating quasi-particles with fractional charges.

Understanding the electrical properties of graphene is important because, unlike the other materials used by the electronics industry, it remains stable and conductive down to the molecular scale. As a result, when the current silicon technology reaches it's a fundamental miniaturization limit in coming years, graphene could very well take its place.

Meanwhile, some theoretical physicists are interested in graphene for a totally different reason: It provides a new way to test their theories.

As electrons move through ordinary metals, they interact with the electrical fields produced by the lattice of metal atoms, which push and pull them in a complex fashion. The net result is that the electrons act as if they have a mass different from that of ordinary electrons. So physicists call this an "effective mass" and consider them to be quasiparticles. When traveling through graphene they also act as quasiparticles, but they behave as if they have a mass of zero. It turns out that graphene quasiparticles, unlike those in other materials, obey the rules of quantum electrodynamics, the same relativistic equations that physicists use to describe the behavior of particles in black holes and high-energy particle accelerators. As a result, this new material may allow physicists to conduct tabletop experiments that test their theoretical models of some of the most extreme environments in the universe.

###

The research was supported by grants from Microsoft Project Q, the Defense Advanced Research Project Agency and the Department of Energy.

[Note: A multimedia version of this story is available on Exploration, Vanderbilt's online research magazine, at www.vanderbilt.edu/exploration/stories/graphene.html]

####

About Vanderbilt University
Vanderbilt University is a center for scholarly research, informed and creative teaching, and service to the community and society at large. Vanderbilt will uphold the highest standards and be a leader in the

* quest for new knowledge through scholarship,
* dissemination of knowledge through teaching and outreach,
* creative experimentation of ideas and concepts.

In pursuit of these goals, Vanderbilt values most highly

* intellectual freedom that supports open inquiry,
* equality, compassion, and excellence in all endeavors.

For more information, please click here

Contacts:
David F. Salisbury

615-343-6803

Copyright © Vanderbilt 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

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

President Obama Meets U.S. Laureates of 2014 Kavli Prizes August 1st, 2014

Stanford researchers seek 'Holy Grail' in battery design: Pure lithium anode closer to reality with development of protective layer of interconnected carbon domes August 1st, 2014

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

Physics

Watching Schrödinger's cat die (or come to life): Steering quantum evolution & using probes to conduct continuous error correction in quantum computers July 30th, 2014

Flexible Metamaterial Absorbers July 29th, 2014

Measuring the Smallest Magnets July 28th, 2014

Physicists Use Computer Models to Reveal Quantum Effects in Biological Oxygen Transport: The team solved a long-standing question by explaining why oxygen – and not deadly carbon monoxide – preferably binds to the proteins that transport it around the body. July 17th, 2014

Possible Futures

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Chip Technology

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

Nanometrics Reports Second Quarter 2014 Financial Results July 30th, 2014

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

A Crystal Wedding in the Nanocosmos July 23rd, 2014

Nanoelectronics

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

A Crystal Wedding in the Nanocosmos July 23rd, 2014

3-D nanostructure could benefit nanoelectronics, gas storage: Rice U. researchers predict functional advantages of 3-D boron nitride July 15th, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Announcements

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

President Obama Meets U.S. Laureates of 2014 Kavli Prizes August 1st, 2014

Stanford researchers seek 'Holy Grail' in battery design: Pure lithium anode closer to reality with development of protective layer of interconnected carbon domes August 1st, 2014

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

President Obama Meets U.S. Laureates of 2014 Kavli Prizes August 1st, 2014

New imaging agent provides better picture of the gut July 25th, 2014

Hysitron is Awarded TWO R&D 100 Awards for Highly Innovative Technology Developments in the Areas of Extreme Environments and Biological Mechanical Property Testing July 23rd, 2014

Researchers create vaccine for dust-mite allergies Main Page Content: Vaccine reduced lung inflammation to allergens in lab and animal tests July 22nd, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE