Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Can Nanotubes Be Engineered to Superconduct?

24.09.2002


Study Suggests Promising New Avenues for Nanotube Research



Superconducting nanotubes may lie on the technology horizon, suggests a theoretical study recently published by researchers from the Commerce Department’s National Institute of Standards and Technology (NIST), the University of Pennsylvania, and Bilkent University in Turkey.

The intriguing possibility is the team’s most recent finding in a spate of studies showing how changing the shape of tiny single-walled tubes of carbon may open a potential mother lode of technologically useful properties. The theoretical investigations are pointing out productive paths for other researchers to follow in experiments that pursue opportunities to make new materials and technologies with nanotubes.


Although formidable obstacles remain, nanotubes were discovered only about a decade ago, and initial product offerings are beginning to edge onto the market.

"Carbon nanotubes are now considered to be building blocks of future electronic and mechanical devices," explains Taner Yildirim, a physicist at the NIST Center for Neutron Research. "We’ll get there quicker if we have a good understanding of the properties of the materials and the interactions among them."

The new calculations by Yildirim and his colleagues indicate that strategically placing hydrogen on the exterior of so-called zigzag nanotubes leads to dense concentrations of charge-carrying electrons just below the material’s conduction band.

In fact, the structure of the molecules-initially resembling cylindrical rolls of chicken wire-becomes rectangular, with a carbon atom at each corner. During the structural makeover, the nanotubes become diamond-like and are transformed from insulators to metals.

The result, says Yildirim, is a "four wire nanocable." Because of the high density of electrons in this particular configuration, he adds, it may be possible to chemically engineer nanotube wires that are superconducting.

Depending on the initial geometry of the nanotubes and on the pattern of hydrogen coverage on tube walls, electronic structures will vary greatly among the resultant materials, as will their properties. The team’s calculations indicate that selective bonding of hydrogen to nanotubes can give rise to a number of potentially useful applications in the emerging field of molecular electronics.

In an earlier study, team members and another collaborator predicted that, when exposed to external pressure, nanotubes will bind tightly and form stable ropelike networks. Published in late 2000, the prediction was later verified in experiments by other researchers.

Subsequent studies published by the team indicate that the chemical and electrical properties of a single-walled carbon nanotubes can be controlled through a reversible process called mechanical deformation. Flattening the radius of a nanotube so that it becomes elliptical, says Yildirim, alters the arrangement of electrons, suggesting an approach to engineering the gap between different bands of electrons within the materials.

"Our calculations indicate that, with radial deformation, it is possible to close the band gap and make an insulating nanotube metallic and vice versa," Yildirim explains. If verified in experiments, this predicted capability could yield new types of carbon-based materials and a host of novel devices built using nanotubes with properties optimized for specific applications.

The work was partially supported by grants from the National Science Foundation and the Scientific and Technical Research Council of Turkey.

As a non-regulatory agency of the U.S. Department of Commerce’s Technology Administration, NIST develops and promotes measurements, standards and technology to enhance productivity, facilitate trade and improve the quality of life.

- 30 -

NOTE: "Effects of hydrogen adsorption on single-wall carbon nanotubes: Metallic hydrogen decoration," by O. Gulseren, T. Yildirim, and S. Ciraci, was published in Physical Review B, Vol. 66, Article121401. A copy of the paper, in Adobe Acrobat PDF format, is available from Mark Bello at mark.bello@nist.gov.

Mark Bello | NIST
Further information:
http://www.ncnr.nist.gov/staff/taner/nanotube/

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>