Superconductors
Finding: Dopants dramatically alter electronic structure of superconductor
February 18, 2013 8:29 am | News | Comments
At present, a key step to achieving superconductivity is to substitute a different kind of atom into some positions of the “parent” material’s crystal framework. Until now, scientists thought this doping process simply added more electrons or other charge carriers, thereby rendering the electronic environment more conducive to the formation of electron pairs that could move with no energy loss if the material is held at a certain chilly temperature. Now, new studies of an iron-based superconductor suggest that the story is somewhat more complicated.
Electron conflict leads to “bad traffic” on way to superconductivity
April 5, 2013 6:28 pm | News | Comments
Rice University physicists on the hunt for the origins of high-temperature superconductivity...
Cuprate superconductors defy convention
March 19, 2013 10:35 am | News | Comments
In physics, Luttinger’s theorem states that the number of electrons in a material is...
Light control on superconducting chip brings quantum devices closer
March 4, 2013 3:05 pm | News | Comments
As one crucial step of achieving controllable quantum devices, physicists at the University of...
Material turns "schizophrenic" on way to superconductivity
April 4, 2013 4:05 pm | News | CommentsRice University physicists on the hunt for the origins of high-temperature superconductivity have published new findings this week about a material that becomes “schizophrenic”—simultaneously exhibiting the characteristics of both a metallic conductor and an insulator. In a theoretical analysis in Physical Review Letters, Rice physicists offer an explanation for a strange series of observations described earlier this year by researchers at the Stanford Linear Accelerator Center in Menlo Park, Calif.
Light particles illuminate the vacuum
February 26, 2013 10:34 am | News | CommentsResearchers in Finland have shown experimentally that vacuum has properties not previously observed. Vacuum contains momentarily appearing and disappearing virtual pairs, which can be converted into detectable light particles. The researchers conducted a mirror experiment to show that by changing the position of the mirror in a vacuum, virtual particles can be transformed into real photons that can be experimentally observed. In a vacuum, there is energy and noise, the existence of which follows the uncertainty principle in quantum mechanics.
A new look at high-temperature superconductors
February 25, 2013 7:49 am | by David L. Chandler, MIT News Office | News | CommentsWhile the phenomenon of superconductivity has been known for more than a century, the temperature at which it occur has remained too low for any practical applications. The discovery of high-temperature superconductors in the 1980s led to speculation that a surge of new discoveries might quickly lead to room-temperature superconductors. Despite intense research, these materials have remained poorly understood. Until now.
Vortex pinning could lead to superconducting breakthroughs
February 13, 2013 8:15 am | News | CommentsA team of researchers announced findings last week that may represent a breakthrough in applications of superconductivity. The team discovered a way to efficiently stabilize tiny magnetic vortices that interfere with superconductivity—a problem that has plagued scientists trying to engineer real-world applications for decades. The discovery could remove one of the most significant roadblocks to advances in superconductor technology.
RABiTS technology enables record-setting performance
January 17, 2013 7:57 am | News | CommentsA technology invented at Oak Ridge National Laboratory for manufacturing copper-oxide-based high-temperature superconducting materials has been used to make an iron-based superconducting wire capable of carrying very high electrical currents under exceptionally high magnetic fields.
Iron-based superconductors set new performance records
January 10, 2013 9:50 am | News | CommentsA collaboration led by scientists at Brookhaven National Laboratory has created a high-performance iron-based superconducting wire that opens new pathways for some of the most essential and energy-intensive technologies in the world. These custom-grown materials carry tremendous current under exceptionally high magnetic fields. The results demonstrate a unique layered structure that outperforms competing low-temperature superconducting wires while avoiding the high manufacturing costs associated with high-temperature superconductor alternatives.
Silver sheds light on superconductor secrets
December 20, 2012 9:52 am | News | CommentsIn the quest for new high transition temperature (TC) superconductors that function above the boiling temperature for liquid nitrogen, the recently developed compound bismuth disulphide has attracted a lot of attention from researchers. By doping this bismuth-based layered material with silver, scientists in China have demonstrated that superconductivity is intrinsic to the new material rather than stemming from its impurities.
A bridge to the quantum world
December 4, 2012 12:35 pm | News | CommentsIn a discovery that helps clear a new path toward quantum computers, University of Michigan physicists have found elusive Dirac electrons in a superconducting material. The combination of properties the researchers identified in a shiny, black material called copper-doped bismuth selenide adds the material to an elite class that could serve as the silicon of the quantum era.
Surprising competition found in high-temperature superconductors
November 14, 2012 2:00 pm | News | CommentsA team led by SLAC National Accelerator Laboratory and Stanford University scientists has made an important discovery toward understanding how a large group of complex copper oxide materials lose their electrical resistance at remarkably high temperatures. The materials in question are high-temperature superconductors, which conduct electricity perfectly with no resistance when cooled below -100 C.
'Strain tuning' reveals promise in nanoscale manufacturing
November 12, 2012 3:22 pm | News | CommentsResearchers at Oak Ridge National Laboratory have reported progress in fabricating advanced materials at the nanoscale. The spontaneous self-assembly of nanostructures composed of multiple elements paves the way toward materials that could improve a range of energy-efficient technologies and data storage devices.
The first controllable atom SQUID
November 7, 2012 9:43 am | News | CommentsScientists at NIST have created the first controllable atomic circuit that functions analogously to a superconducting quantum interference device (SQUID) and allows operators to select a particular quantum state of the system at will. By manipulating atoms in a superfluid ring thinner than a human hair the investigators were able for the first time to measure rotation-induced discrete quantized changes in the atoms’ state, thereby providing a proof-of-principle design for an “atomtronic” inertial sensor.
Cocktail achieves superconducting boost
October 30, 2012 1:59 pm | News | CommentsScientists have recently developed a high-performance superconducting material by mixing iron and selenium in a new chemistry. Although this class of superconductors has already existed, the new material is the first to break the 44 Kelvin barrier. It also shows that iron-selenium superconductors can be successfully synthesized to a high degree of purity.
A robust home for qubits
October 9, 2012 12:42 pm | News | CommentsIn 1937, Italian physicist Ettore Majorana predicted the existence of a class of particle that would serve as its own antiparticle. Such a particle might exist as a quasiparticle, or collection of excitons. Some scientists believe that qubits made from these Majorana “pulses”, when excited in topological materials, would be much more immune from decoherence than other qubits based on conventional particles.
High-temperature superconductivity induced in semiconductor with tape
September 11, 2012 11:30 am | News | CommentsAn international team led by University of Toronto physicists has developed a simple new technique using Scotch poster tape that has enabled them to induce high-temperature superconductivity in a semiconductor for the first time. The method paves the way for novel new devices that could be used in quantum computing and to improve energy efficiency.
X-rays reveal spin waves in 2D high-temperature superconductors
September 4, 2012 3:29 am | News | CommentsPhysicists working at Brookhaven National Laboratory and Switzerland's Paul Scherrer Institute have revealed key quantum characteristics of high-temperature superconductors, demonstrating new experimental methods and breaking fundamental ground on these mysterious materials.
Superconductor 'flaws' could be key to its abilities
August 23, 2012 4:04 am | News | CommentsPhysicists who study superconductivity strive to create a clean, perfect sample. But a Purdue University team that has mapped seemingly random, four-atom-wide dark lines of electrons on the surface of copper-oxygen based superconducting crystals has discovered that they exist throughout the crystal. The findings suggest the lines, which are “flaws”, could play a role in the material's superconductivity at much higher temperatures than others.
Unraveling the mysteries of exotic superconductors
June 25, 2012 9:10 am | News | CommentsScientists at Ames Laboratory are using specialized techniques to help unravel the mysteries of a new type superconductor. The group was part of an international collaboration that found that magnetism may be helping or even responsible for superconductivity in iron-based superconductors.
Asymmetry may provide clue to superconductivity
June 20, 2012 10:05 am | News | CommentsJapanese and U.S. physicists are offering new details regarding intriguing similarities between the quirky electronic properties of a new iron-based high-temperature superconductor (HTS) and its copper-based cousins. While investigating a recently discovered iron-based HTS, the researchers found that its electronic properties were different in the horizontal and vertical directions.
Helping superconductors turn up the heat
June 18, 2012 6:55 am | News | CommentsResearchers from the University of Miami are unveiling a novel theory for high-temperature superconductivity. The team hopes the new finding gives insight into the process, and brings the scientific community closer to achieving superconductivity at higher temperatures than currently possible.
Scientists observe electrons become both heavy and speedy
June 14, 2012 3:42 am | News | CommentsA Princeton University-led team of scientists has shown how electrons moving in certain solids can behave as though they are a thousand times more massive than free electrons, yet at the same time act as speedy superconductors.
Theorem unifies superfluids and other weird materials
June 11, 2012 5:01 am | News | CommentsMatter exhibits weird properties at very cold temperatures. Take superfluids, for example: discovered in 1937, they can flow without resistance forever, spookily climbing the walls of a container and dripping onto the floor. In the past 100 years, 11 Nobel Prizes have been awarded to nearly two dozen people for the discovery or theoretical explanation of such cold materials, yet a unifying theory of these extreme behaviors has eluded theorists, until now.
New clues to high-temperature conductivity
May 31, 2012 10:58 am | News | CommentsUsing ultrafast lasers, Lawrence Berkeley National Laboratory scientists have tackled the long-standing mystery of how Cooper pairs form in high-temperature superconductors. With pump and probe pulses spaced just trillionths of a second apart, the researchers used photoemission spectroscopy to map rapid changes in electronic states across the superconducting transition, revealing relationships of energy and momentum never seen before in these promising, but stubborn, complex materials.
High-temperature superconductivity starts with nanoscale electronic oases
May 31, 2012 5:04 am | by Bill Steele, Cornell University | News | CommentsHigh-temperature superconductivity doesn't happen all at once. It starts in isolated nanoscale patches that gradually expand until they take over. That discovery, from atomic-level observations at Cornell University and the University of Tokyo, offers a new insight into the puzzling " pseudogap " state observed in high-temperature superconductors.
Iron-based superconductors exhibit s-wave symmetry
May 18, 2012 4:16 am | News | CommentsCondensed-matter physicists the world over are in hot pursuit of a comprehensive understanding of high-temperature superconductivity, not just for its technological benefits but for the clues it holds to strongly correlated electron systems. One important avenue of investigation is pairing symmetry.
Atomic-scale visualization of electron pairing in iron superconductors
May 4, 2012 4:05 am | News | CommentsBy measuring how strongly electrons are bound together to form Cooper pairs in an iron-based superconductor, scientists provide direct evidence supporting theories in which magnetism holds the key to this material’s ability to carry current with no resistance. This research strengthens confidence that this type of theory may one day be used to identify or design new materials with improved properties.
