Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Physicists unlock nature of high-temperature superconductivity

29.07.2014

Physicists have identified the "quantum glue" that underlies a promising type of superconductivity -- a crucial step towards the creation of energy superhighways that conduct electricity without current loss.

The research, published online in the Proceedings of the National Academy of Sciences, is a collaboration between theoretical physicists led by Dirk Morr, professor of physics at the University of Illinois at Chicago, and experimentalists led by Seamus J.C. Davis of Cornell University and Brookhaven National Laboratory.


This is UIC physicist Dirk Morr, who worked with researchers at Brookhaven National Laboratory, says the findings were the result of 'the close collaboration of theory and experiment.'

Credit: Photo: Roberta Dupuis-Devlin/UIC Photo Services

The earliest superconducting materials required operating temperatures near absolute zero, or −459.67 degrees Fahrenheit. Newer unconventional or "high-temperature" superconductors function at slightly elevated temperatures and seemed to work differently from the first materials. Scientists hoped this difference hinted at the possibility of superconductors that could work at room temperature and be used to create energy superhighways.

Superconductivity arises when two electrons in a material become bound together, forming what is called a Cooper pair. Groundbreaking experiments performed by Freek Massee and Milan Allan in Davis's group were analyzed using a new theoretical framework developed at UIC by Morr and graduate student John Van Dyke, who is first author on the report.

Their results pointed to magnetism as the force underlying the superconductivity in an unconventional superconductor consisting of cerium, cobalt and indium, with the molecular formula CeCoIn5.

"For a long time, we were unable to develop a detailed theoretical understanding of this unconventional superconductor," said Morr, who is principal investigator on the study. Two crucial insights into the complex electronic structure of CeCoIn5 were missing, he said: the relation between the momentum and energy of electrons moving through the material, and the 'quantum glue' that binds the electrons into a Cooper pair.

Those questions were answered after the Davis group developed high-precision measurements of CeCoIn5 using a scanning tunneling spectroscopy technique called quasi-particle interference spectroscopy. Analysis of the spectra using a novel theoretical framework developed by Morr and Van Dyke allowed the researchers to extract the missing pieces of the puzzle.

The new insight allowed them to explore the 30-year-old hypothesis that the quantum glue of superconductivity is the magnetic force.

Magnetism is highly directional, Morr said.

"Knowing the directional dependence of the quantum glue, we were able, for the first time, to quantitatively predict the material's superconducting properties using a series of mathematical equations," he said.

"Our calculations showed that the gap possesses what's called a d-wave symmetry, implying that for certain directions the electrons were bound together very strongly, while they were not bound at all for other directions," Morr said. Directional dependence is one of the hallmarks of unconventional superconductors.

"We concluded that magnetism is the quantum glue underlying the emergence of unconventional superconductivity in CeCoIn5."

The finding has "lifted the fog of complexity" surrounding the material, Morr said, and was only made possible by "the close collaboration of theory and experiment, which is so crucial in advancing our understanding of complex systems."

"We now have an excellent starting point to explore how superconductivity works in other complex material," Morr said. "With a working theory, we can now investigate how we have to tweak the system to raise the critical temperature -- ideally, all the way up to room temperature."

###

In addition to those mentioned above, Cedomir Petrovic of Brookhaven National Laboratory is a co-author on the study.

The research was supported by the U.S. Department of Energy under Contract DEAC02‐98CH10886 at Brookhaven and Award DE‐FG02‐05ER46225 at UIC.

Jeanne Galatzer-Levy | Eurek Alert!
Further information:
http://www.uic.edu/uic/

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>