Hydrocarbon superconductor created

Mar 10, 2010 by Lin Edwards report
Molecular structure, crystal structure and physical appearance of picene. Photographs show pristine picene (top; white) and Kxpicene (bottom; black). Image credit: Nature.

(PhysOrg.com) -- Scientists from Okayama University in Japan have discovered that the hydrocarbon picene can be made to superconduct when potassium atoms are interspersed with the picene crystals and the doped picene is cooled.

Electricity flows through a superconductor with no resistance when the material is chilled to below a (Tc). The phenomenon was discovered in 1911 by Dutch scientist Heike Kamerlingh Onnes, who demonstrated the lack of resistance by creating an in a closed loop of a mercury superconductor. After the driving potential was removed, the current continued to flow even on the journey from the Netherlands to England.

Picene (C22H14) is an organic compound found occurring naturally in coal tar, and in residues of the petroleum refining process. It is usually a semiconductor, but the researchers, led by Yoshihiro Kubozono, found that when synthesized picene is doped (intercalated) with atoms of an alkali such as or potassium it became a superconductor with a Tc of 18 kelvin (-255 degrees Celsius) or below, which is a relatively high temperature for superconductors. Professor Kubozono said picene is the first example of a superconductor, although scientists have been able to create superconductors of the carbon compound fullerene (C60) doped with potassium.

The picene molecule resembles five benzene rings joined in a staggered line, and is a flat molecule that stacks into layers to form crystals. The researchers cooked picene with potassium, which forced the alkali atoms between the layers and improved its conductivity in planes parallel to the layers.

The researchers are now trying other metals with picene, including and sodium, and are testing other hydrocarbons for superconductivity. Their research paper is published in Nature. A commentary in the journal, by Kosmas Prassides of Durham University, described the work as "exciting news for superconductivity researchers". He predicted it would stimulate more work on hydrocarbons to confirm the work of the Japanese researchers and to find other hydrocarbons that can be coaxed into becoming .

Explore further: Warming up the world of superconductors

More information: Superconductivity in alkali-metal-doped picene, Ryoji Mitsuhashi et al., Nature 464, 76-79 (4 March 2010). doi:10.1038/nature08859

Related Stories

New material could help cut future energy losses

Mar 19, 2009

Scientists at the University of Liverpool and Durham University have developed a new material to further understanding of how superconductors could be used to transmit electricity to built-up areas and reduce global energy ...

Secrets behind high temperature superconductors revealed

Feb 22, 2009

(PhysOrg.com) -- Scientists from Queen Mary, University of London and the University of Fribourg (Switzerland) have found evidence that magnetism is involved in the mechanism behind high temperature superconductivity.

Putting the Pressure on Iron-Based Superconductors

Mar 05, 2009

(PhysOrg.com) -- Traditionally, magnetism and superconductivity don't mix. For more than 20 years, the only known superconductors that worked at so-called "high" temperatures (above 30 K, or about -406 degrees ...

Superconductivity in diamond

Apr 10, 2004

As well as holding pride of place as the most sought-after of all precious gemstones, diamond possesses a dazzling array of technologically useful properties. As well as being the hardest, most thermally conducting, ...

Recommended for you

New filter could advance terahertz data transmission

Feb 27, 2015

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

Feb 27, 2015

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

Precision gas sensor could fit on a chip

Feb 27, 2015

Using their expertise in silicon optics, Cornell engineers have miniaturized a light source in the elusive mid-infrared (mid-IR) spectrum, effectively squeezing the capabilities of a large, tabletop laser onto a 1-millimeter ...

A new X-ray microscope for nanoscale imaging

Feb 27, 2015

Delivering the capability to image nanostructures and chemical reactions down to nanometer resolution requires a new class of x-ray microscope that can perform precision microscopy experiments using ultra-bright ...

New research signals big future for quantum radar

Feb 26, 2015

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University ...

User comments : 6

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (4) Mar 10, 2010
Superconductivity does not like warmth. Warmth does nothing else then shakes atoms. From that can be concluded that superconductivity does not like shaking. This mean for high temperature superconductivity shaking must be suppressed. There are only two possibilities to suppress atoms thermal motion: first is using strong chemical bounds (suppress amplitude but increase speed) and second is using really heavy atoms (suppress both amplitude and speed). Anybody ever tray to use depleted Uranium for doping?
not rated yet Mar 10, 2010
@taka -

your incorrect statements must be because English is not your first language (that's not a criticism of your English, just of your poor understanding of superconductivity). Superconductive states MUST be preceded by specific types of phonon propagation, which are, BY DEFINITION, quantized vibrations of the crystal lattice. The trick is to figure out how to manage these vibrations and, most importantly, to figure out WHY phonon propagation is so critical to superconductivity @ T_c.
1 / 5 (1) Mar 10, 2010
Flexible, easily extruded, superconducting cables here we come! :)
not rated yet Mar 11, 2010
I made no assumptions of how it works. Just pure logic. Sometimes it is better to abstract from details and tray to see the big picture. And it is not in contradiction with phonons, for them the thermal movement may be disturbing noise. But it leaves the question of why it switches on and off so rapidly when temperature changes, thermal movement changes gradually and atoms do not change its arrangement! And yes, English is not my first language.
not rated yet Mar 12, 2010
While its true that most superconductivity has a very sharp cutoff, other properties such as current carrying capacity do not. Generally speaking, thermal disruption causes defect growth (vortexes), limiting the amount of material available to super conduct (and current carrying capacity), until at the cutoff the defects completely overwhelm the material.
not rated yet Mar 22, 2010
Existence of quantified phonons may prevent electrons to transform its energy into heat. If electron moves near atom it influence atom by its e field and shake it (it do not need to hit atom directly for that), this shaking generates heat and this mean also resistance. If there is quantified phonon this shaking is too small to push phonon to next energy level and so electron (current) cannot lose its energy. But something must simultaneously prevent electrons from being accelerated (if atoms cannot get energy from electrons they also cannot decrease electrons speed), or electrons will eventually get enough energy to overcome this phonon barrier.

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.