Superconductivity: Which one of these is not like the other?

July 13, 2009
Superconductivity appears to rely on very different mechanisms in two varieties of iron-based superconductors. Credit: American Physical Society [Illustration: Alan Stonebraker]

Superconductivity appears to rely on very different mechanisms in two varieties of iron-based superconductors. The insight comes from research groups that are making bold statements about the correct description of superconductivity in iron-based compounds in two papers about to be published in journals of the American Physical Society.

The 2008 discovery of in iron-based compounds has led to a flood of research in the past year. As the literature mounts on these materials, which superconduct at temperatures as high as 55 K, two key questions are emerging: Is the origin of superconductivity in all of the iron-based compounds the same and are these materials similar to the copper oxide-based high-temperature superconductors (commonly known as cuprates), which physicists have studied for nearly twenty years but are still unable to explain with a complete theory?

These questions are addressed separately in two papers highlighted in the July 13 issue of Physics. A collaboration between scientists at Lawrence Berkeley National Lab, the SLAC National Accelerator Laboratory, Stanford University and institutions in Switzerland, China, Mexico and the Netherlands reports in Physical Review B x-ray experiments indicating that, in iron-based superconductors that contain arsenic or phosphorous (called 'iron pnictides'), the electrons that ultimately pair to form the superconducting state behave differently than those in the cuprates. More specifically, while the electrons in the cuprates are strongly correlated - meaning the energy of one electron is tied to the energy of the others - the electrons in the iron-pnictide superconductors behave more like those of a normal metal in which the electrons do not (to first approximation) interact.

In a paper appearing in , scientists at Princeton, UC Berkeley and Shanghai Jiao Tong University in China present the first photoemission measurements on an iron-based superconductor that contains tellurium, Fe1+xTe. They argue the origin of superconductivity in this type of iron compound, which belongs to a class of materials called the iron-chalcogenides, has a different origin than in the arsenic and phosphorous containing iron-pnictides. In fact, the measurements suggest that in the iron-chalcogenides may be more similar to that of the cuprates.

The statements put forth in these two articles are likely to influence the direction taken by physicists who work on the theory of iron-based . See the Viewpoint article in the July 13 issue of APS Physics to learn more.

More information:

Source: American Physical Society

Explore further: Scientists prove unconventional superconductivity in new iron arsenide compounds

Related Stories

Putting the Pressure on Iron-Based Superconductors

March 5, 2009

( -- 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 Fahrenheit) ...

Physicists offer new theory for iron compounds

March 12, 2009

An international team of physicists from the United States and China this week offered a new theory to both explain and predict the complex quantum behavior of a new class of high-temperature superconductors.

Magnetism Governs Properties of Iron-Based Superconductors

March 18, 2009

( -- Though a year has passed since the discovery of a new family of high-temperature superconductors, a viable explanation for the iron-based materials’ unusual talent remains elusive. But a team of scientists ...

Recommended for you

Exploring the physics of a chocolate fountain

November 24, 2015

A mathematics student has worked out the secrets of how chocolate behaves in a chocolate fountain, answering the age-old question of why the falling 'curtain' of chocolate surprisingly pulls inwards rather than going straight ...

Biomedical imaging at one-thousandth the cost

November 23, 2015

MIT researchers have developed a biomedical imaging system that could ultimately replace a $100,000 piece of a lab equipment with components that cost just hundreds of dollars.


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Jul 13, 2009
The more variations, the merrier...

Perhaps a 'pattern' will emerge.
not rated yet Jul 13, 2009
my new favourite word : pnictides, ;-), but on a serious note, I agree with with Nik
Jul 13, 2009
This comment has been removed by a moderator.

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.