Physicists discover surprising variation in superconductors

Jan 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: Detecting neutrinos, physicists look into the heart of the Sun

add to favorites email to friend print save as pdf

Related Stories

To bolster lithium battery life, add a little salt

Aug 14, 2014

( —Cornell chemical engineers have achieved a breakthrough in the race to achieve safer, longer-lasting batteries to power the world's automobiles, cell phones, computers and autonomous robots.

New material structures bend like microscopic hair

Aug 06, 2014

MIT engineers have fabricated a new elastic material coated with microscopic, hairlike structures that tilt in response to a magnetic field. Depending on the field's orientation, the microhairs can tilt to ...

Beyond tapping and sliding

Aug 06, 2014

"The way we design computers today," Microsoft researcher Hong Tan says, "it would seem that people only use their eyes."

The perfect atom sandwich requires an extra layer

Aug 05, 2014

( —Like the perfect sandwich, a perfectly engineered thin film for electronics requires not only the right ingredients, but also just the right thickness of each ingredient in the desired order, ...

Recommended for you

Awakening the potential of plasma acceleration

13 hours ago

Civil engineering has begun for the new Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN. This proof-of-principle experiment will harness the power of wakefields generated by proton ...

Magnetic memories on the right track

13 hours ago

Computer hard drives store data by writing magnetic information onto their surfaces. In the future, magnetic effects may also be used to improve active memory in computers, potentially eliminating the need ...

When an exciton acts like a hole

15 hours ago

( —When is an electron hole like a quasiparticle (QP)? More specifically, what happens when a single electron hole is doped into a two-dimensional quantum antiferromagnet? Quasiparticle phenomena ...

User comments : 0