Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Research on "Holes" May Unearth Causes of Superconductivity


Scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have uncovered another possible clue to the causes of high-temperature superconductivity, a phenomenon in which the electrical resistance of a material disappears below a certain temperature. In a superconducting compound, they found evidence of a rarely seen arrangement of “holes” – locations where electrons are absent. The results appear in the October 28, 2004, issue of Nature.

The researchers were studying a compound made of strontium, copper, and oxygen (which they’ve dubbed SCO) that is one of the “cuprates,” a family of compounds that contain copper oxide. In SCO, the scientists found evidence of a “hole crystal” – a rigid, ordered arrangement of holes. Holes are positively charged and, like electrons, may interact with each other to produce a superconducting current. “A hole crystal is a very unusual phenomenon,” said Brookhaven physicist Peter Abbamonte, the study’s lead researcher. “Its existence is a direct result of the correlations between holes, which are believed to produce superconductivity in other cuprates.”

SCO consists of one layer of strontium atoms sandwiched by two sheets of different copper oxides. In one sheet, the copper-oxide molecules form long, parallel chains. The other copper-oxide layer, which contains the hole crystal, has a ladder structure, resembling chains that are linked horizontally. A hole crystal is just one type of arrangement of electric charge in a material. These arrangements are important because some researchers believe that superconductivity is the result of a particular arrangement, or occurs when a superconductor approaches a boundary between two arrangements. In other cuprates, for example, scientists are studying a charge arrangement in which ribbons of holes and magnetic regions form alternating “stripes.” “We believe the hole crystal and stripes may be linked,” said Abbamonte. “Specifically, the hole crystal in SCO may be a ‘low-dimensional’ precursor to stripes, meaning it exists only along the copper-oxide ladders, rather than in an entire copper-oxide plane.”

He and his collaborators studied SCO using x-rays from the National Synchrotron Light Source, a facility at Brookhaven Lab that produces x-ray, ultraviolet, and infrared light for research in a variety of scientific fields. They placed an SCO sample in the path of an x-ray beam, varied the wavelength of the beam, and watched how the x-rays reflected away from the sample.

At a particular energy, the sample reflected back the x-rays very intensely. The research group discovered that this reflection was caused by the holes, which led them to determine that the holes formed an ordered lattice since randomly placed holes could not have produced such a strong reflection.

Abbamonte and his collaborators plan to continue this research by varying the chemical composition of SCO to see if it changes the hole crystal. They will also examine another cuprate to see if its stripes are related to the crystal. “Clearly, more research needs to be done to study these phases and their possible link to superconductivity,” said Abbamonte.

The research was funded by the Office of Basic Energy Sciences within the U.S. Department of Energy’s Office of Science, the National Science Foundation, Bell Laboratories, the Dutch Science Foundation, and the Netherlands Organization for Fundamental Research on Matter.

Laura Mgrdichian | EurekAlert!
Further information:

More articles from Power and Electrical Engineering:

nachricht New method increases energy density in lithium batteries
24.10.2016 | Columbia University School of Engineering and Applied Science

nachricht 'Super yeast' has the power to improve economics of biofuels
18.10.2016 | University of Wisconsin-Madison

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Enormous dome in central Andes driven by huge magma body beneath it

25.10.2016 | Earth Sciences

First time-lapse footage of cell activity during limb regeneration

25.10.2016 | Life Sciences

Deep down fracking wells, microbial communities thrive

25.10.2016 | Earth Sciences

More VideoLinks >>>