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 APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie

nachricht First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science

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: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>