Physicists discover surprising variation in superconductors

January 28, 2009 By Anne Trafton

( -- MIT physicists have discovered that several high-temperature superconductors display patchwork quilt-like variations at the atomic scale, a surprising finding that could help scientists understand a new class of unconventional materials.

The researchers said the variation in a property known as the Fermi surface, which has never been seen before in any kind of material, could just be an oddity. But it could also serve as an important clue for physicists working to unravel the mystery of why a broad new class of materials exhibits exotic properties from high-temperature superconductivity (the ability to carry electricity with no resistance) to colossal magneto-resistance (the ability to dramatically change electrical resistance when a magnetic field is applied).

In such materials, known as strongly correlated electronic materials, interactions between electrons, normally weak enough that they can essentially be ignored, dominate the physics of the material, leading to a host of unexplained phenomena.

"These materials are so unusual that we decided to check for variations that would normally be impossible -- and there they were," said Eric Hudson, associate professor of physics and senior author of a paper on the work that appeared online in Nature Physics Jan. 25.

Hudson and colleagues found that the Fermi surface, a measurement of the distribution of electrons in a material, varies at the atomic scale across the surface of two bismuth-based superconductors, which belong to the class of strongly correlated electronic materials. Until now, it was believed that Fermi surface was uniform throughout any material.

"The idea that electrons separated by just an atom's distance can behave so differently is astonishing," Hudson said.

The discovery that electronic properties can vary so much on the nanoscale could shed light on how this class of materials deals with strongly interacting electrons, and how their unusual properties arise, he said.

To study the Fermi surface, the researchers used a common technique called scanning tunneling microscopy, which, combined with a new analysis method called quasiparticle interference, can reveal, on an atom-by-atom basis, what electrons are doing.

Lead author of the paper is physics graduate student William Wise. Other MIT authors are graduate student Kamalesh Chatterjee; former graduate student Michael Boyer; and former postdoctoral associates Takeshi Kondo and Yayu Wang. Researchers from Nagoya University in Japan and Brookhaven National Laboratory also contributed to the work.

Provided by MIT

Explore further: 'Material universe' yields surprising new particle

Related Stories

'Material universe' yields surprising new particle

November 25, 2015

An international team of researchers has predicted the existence of a new type of particle called the type-II Weyl fermion in metallic materials. When subjected to a magnetic field, the materials containing the particle act ...

Atom-sized craters make a catalyst much more active

November 24, 2015

Bombarding and stretching an important industrial catalyst opens up tiny holes on its surface where atoms can attach and react, greatly increasing its activity as a promoter of chemical reactions, according to a study by ...

Recommended for you

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

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 ...


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.