CARBON WORLDSSuperconductivity Taken To The Nanoth Degree
Physicists at the Hong Kong University of Science and Technology have discovered that, below 15 K, single 4-Angstrom-carbon nanotubes exhibit superconductivity. This is the first time single-carbon nanotubes have been found to show superconducting properties.
In recognition of this major breakthrough, Science, the world's top science journal, published the research findings on 29 June 2001. The discovery has also been reported by Chemical & Engineering News, PhysicsWeb, sina.com and People's Daily so far.
Superconductivity is a property of some materials which, when cooled to temperatures within several degrees above absolute zero (-273 C, often written as O Kelvin, K), lose all their electrical resistance. However, pure carbon, an element present in all life forms, has never been found to superconduct.
The HKUST physicists, led by Prof Ping Sheng, have demonstrated that when pure carbon is rolled into ultra tiny tubes, it becomes superconducting.
This research represents another major breakthrough for HKUST researchers on single-walled carbon nanotubes. Last November, HKUST physicists used microporous zeolite single crystals as hosts to fabricate the world's smallest single-walled carbon nanotubes (SWNTs), which possess diameters of only 0.4 nm (nanometer).
Dr Zikang Tang, assistant professor of the Physics Department, predicted then that the carbon nanotube could be an ideal one-dimensional conductor although its novel properties were yet to be explored.
Based on the success of their creation, Dr Tang and his colleagues have unraveled one of the most perplexing puzzles and discovered the signature of one dimensionality in superconductivity.
As the single-walled carbon nanotubes are uniform in size, regularly arrayed but isolated from each other in the zeolite matrix, they constitute an almost ideal one-dimensional (1D) system.
"In a famous theorem published some 40 years ago, physicists Mermin and Wagner proved that it is impossible for abrupt superconducting transition to occur in one- or two-dimensional worlds," said Prof Ping Sheng, Head of the Physics Department and Director of HKUST's newly established Institute of Nano Science and Technology.
"Our experiments and observations have confirmed the one-dimensionality effect, with extensive theoretical calculations. This will open up new horizons in basic and applied research into 1D superconductivity," said Sheng.
While the research is significant in terms of its scientific breakthrough, practical applications are yet to be discovered. "It's far too early to predict anything concerning potential applications. Nevertheless, history tells us that all new material properties are eventually translated into useful applications," said Prof Sheng.
"However, as the 0.4nm single-walled carbon nanotubes are at or close to their theoretical limit, they are probably the smallest wire that we can produce, and will open the door to nanocircuitries with low dissipation," he added.
Prof Sheng attributed the success of the research to collaborative efforts by colleagues at HKUST's Physics Department in the past three years.
"For any research to succeed, three elements are needed: novel sample fabrication; experimentation and characterization; and theory and simulation. Without any of these elements, we would not have been able to conduct the research, nor could we understand and explain the properties of the materials."
"I also hope that Hong Kong people will be able to share our pride. This discovery has been made in Hong Kong by local researchers, right from its inception to its present publication. This demonstrates that Hong Kong researchers are capable of achieving major scientific breakthroughs," he said.
Led by Prof Ping Sheng, the research on "Superconductivity in 4-Å Single-Walled Carbon Nanotubes" was undertaken by Dr Zikang Tang, Dr Lingyun Zhang, Dr Ning Wang, Dr Xixiang Zhang, G H Wen, G D Li, Dr Jiannong Wang, and Dr Che Ting Chan.
Hong Kong University of Science and Technology
Subscribe To SpaceDaily Express
CARBON WORLDSCo2 Fluid Could Make Chips Clean
Los ALamos - Feb. 7, 2001
Scientists at the Department of Energy's Los Alamos National Laboratory have developed a new technology application that could all but eliminate the use of hazardous corrosives and the production of wastewater in the fabrication of integrated circuits, or chips, for computers.
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.|