Small graphene wires may be poor conductors

Feb 15, 2008

Ohio University physicists researching electron properties in graphene ribbons have found that narrow wires made of this material may not be good conductors.

Graphene is considered to be the natural successor for silicon — the semiconductor material comprising the majority of all electronics today — with potential applications in the development of transistors and other circuitry devices that can revolutionize the future of electronics, said Nancy Sandler, an assistant professor of physics and astronomy at Ohio University.

Sandler, in collaboration with Ohio University postdoctoral fellow Mahdi Zarea, began researching electron phenomena in graphene — a single planar sheet of carbon-bonded atoms that forms graphite in its layered form — a year ago. The researchers were intrigued by the properties of the material when confined to small dimensions and focused on ribbon geometries as a first attempt to understand graphene wires.

“Under certain conditions carbon is a better conductor than silicon,” said Sandler. “With graphene, only a minimum push — with a very small energy cost — is required to stimulate electrons to move. They can move faster and without deviations from their path even at room temperatures.”

However, this behavior changes dramatically if the material is made into very thin wires, as the researchers found out in their latest work, which recently was published in the journal Physical Review Letters and in the Virtual Journal of Nanoscale Science & Technology.

The published work contains the first proposal of an explicit mechanism proved to dramatically alter the expected conduction properties of graphene ribbons.

“There are ‘minimum widths’ below which graphene ribbons are simply not good conductors at room temperatures. If we want to have smaller circuits, we need somehow to deal with the laws of repulsion that govern nature at such small scales,” Sandler said.

The effect is basically caused by the natural repulsion that alike charges feel when placed closer, when they are ‘confined,’ said Zarea. Surprisingly, and in contrast to predictions for graphene planes, intrinsic spin-orbit interactions originating from electrons moving around one another in which their spins can alter the motion — an effect due to relativistic corrections — don’t have the same consequences. It’s not the way electrons move, but their closeness that is fundamental in establishing the material's metallic behavior and viability as a conductor material, according to the researchers.

Sandler and Zarea are members of Ohio University’s Nanoscale and Quantum Phenomena Institute.

Source: Ohio University

Explore further: Cooling with the coldest matter in the world

add to favorites email to friend print save as pdf

Related Stories

Nanotube growth theory experimentally confirmed

Jan 30, 2012

(PhysOrg.com) -- The Air Force Research Laboratory in Dayton, Ohio, has experimentally confirmed a theory by Rice University Professor Boris Yakobson that foretold a pair of interesting properties about nanotube ...

Engineers discover graphene's weakness

Dec 09, 2010

(PhysOrg.com) -- If you owned a mechanical device made out of the strongest material known to mankind, wouldn’t you want to know under what circumstances it might fail?

Recommended for you

Cooling with the coldest matter in the world

6 hours ago

Physicists at the University of Basel have developed a new cooling technique for mechanical quantum systems. Using an ultracold atomic gas, the vibrations of a membrane were cooled down to less than 1 degree ...

Magnetic fields and lasers elicit graphene secret

6 hours ago

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have studied the dynamics of electrons from the "wonder material" graphene in a magnetic field for the first time. This led to the discovery of ...

New 2-D quantum materials for nanoelectronics

Nov 21, 2014

Researchers at MIT say they have carried out a theoretical analysis showing that a family of two-dimensional materials exhibits exotic quantum properties that may enable a new type of nanoscale electronics.

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

NeilFarbstein
5 / 5 (1) Feb 15, 2008
why are they moving around one another? That sound like superconductive behavior, coooper pairs.
earls
5 / 5 (1) Feb 15, 2008
they're good conductors minus the configuration they're forcing them to assume
Jkirk3279
not rated yet Feb 18, 2008
"Very thin wires".... just HOW thin?

Does this refer to the carbon nanotubes? Funny, I would have thought that having the cylindrical surface area of a nanotube would allow for sufficient charge separation.

Perhaps the hollow nanotube could be 'doped' with another semiconductor to overcome the problem.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.