Phys.org March 10, 2022 In high-temperature superconductors, at a certain “critical point,” electrons seem to vanish from the Fermi surface map. To understand this phenomenon and engineer that property into some other material that is easier to adopt in technologies, an international team of researchers (USA – Cornell University, UT Austin, National High Magnetic Field Laboratory, Binghamton University, Canada, France, UK) discovered that magnetism is key to understanding the behavior of electrons in “high-temperature” superconductors. They measured the Fermi surface of a copper-oxide high temperature superconductor as a function of electron concentration, right around the critical point and found that […]
Tag Archives: Superconductors
Study raises new possibilities for triggering room-temperature superconductivity with light
Phys.org March 9, 2022 In the case of the superconducting material yttrium barium copper oxide, or YBCO, experiments have shown that under certain conditions, knocking it out of equilibrium with a laser pulse allows it to superconduct at much closer to room temperature than researchers expected. YBCO switches from a normal to a superconducting state when chilled below a certain transition temperature or it can be switched off with a pulse of light. An international team of researchers (South Korea, USA – SLAC National Accelerator Laboratory, Japan, Germany) compared the two switching approaches (exposing to high magnetic field and laser […]
Moments of silence point the way towards better superconductors
Science Daily December 20, 2021 Superconductivity depends on the presence of electrons bound together in a Cooper pair, but they break dissipating into two quasiparticles that hamper the performance of superconductors. It is not clear why Cooper pairs break, but the presence of quasiparticles introduces noise into technologies based on superconductors. Through an experimental set up an international team of researchers (Finland, Sweden) showed that in micron-scale aluminium superconductor separated from metallic copper by a thin insulating layer, the broken Cooper pairs the quasiparticles would tunnel through the insulation to the copper. The Cooper pairs break in bursts, with seconds […]
Discovery of two-phase superconductivity in CeRh2As2
Science Daily August 26, 2021 Although tens of unconventional superconductors have been discovered in the past half century, there was good thermodynamic evidence of more than one superconducting phase in only one or two materials. An international team of researchers (Germany, New Zealand, UK) used thermodynamic probes to establish two-phase superconductivity in CeRh2As2. Both materials have the highest critical magnetic field to superconducting transition temperature ratio of any known superconductor. The findings can be expected to generate entirely new research directions…read more. TECHNICAL ARTICLE
Scientists have synthesized a new high-temperature superconductor
Phys.org March 10, 2021 An international team of researchers (Russia, USA – University of Chicago, Spain, Italy, China) performed theoretical and experimental research on yttrium hydride (YH6), one among the three highest-temperature superconductors known to date. All these hydrides reach their maximum superconductivity temperatures at very high pressures. The current challenge is to attain room-temperature superconductivity at lower pressures. In the case of YH6, the agreement between theory and experiment is rather poor. For example, the critical magnetic field observed in the experiment is 2 to 2.5 times greater as compared to theoretical predictions. This is the first-time scientists encounter such […]
Room-temperature superconductor? Rochester lab sets new record toward long-sought goal
University of Rochester October 14, 2020 A team of researchers in the US (University of Rochester, industry, University of Nevada) reported superconductivity in a photochemically transformed carbonaceous sulfur hydride system, starting from elemental precursors, with a maximum superconducting transition temperature of 287.7 ± 1.2 kelvin (about 15 degrees Celsius) achieved at 267 ± 10 gigapascals. The superconducting state was observed over a broad pressure range in the diamond anvil cell. Superconductivity was established by the observation of zero resistance, a magnetic susceptibility of up to 190 gigapascals, and reduction of the transition temperature under an external magnetic field of up […]
New type of superconductor identified
Science Daily September 21, 2020 Strontium ruthenate (Sr2RuO4) has stood as the leading candidate for a spin-triplet superconductor for 26 years. Using resonant ultrasound spectroscopy an international team of researchers (USA – Cornell University, Florida State University, Germany, Japan) measured the entire symmetry-resolved elastic tensor Sr2RuO4 through the superconducting transition. They found a thermodynamic discontinuity in the shear elastic modulus which implies that the superconducting order parameter has two components, a two-component p-wave order parameter. As this order parameter appears to have been precluded by recent NMR experiments, they suggest that two other two-component order parameters are now the prime […]
Closely spaced hydrogen atoms could facilitate superconductivity in ambient conditions
Phys.org February 3, 2020 An international team of researchers (Switzerland, USA – University of Illinois, Oak Ridge National Laboratory, Poland) conducted neutron scattering experiments on zirconium vanadium hydride at atmospheric pressure and at temperatures from -450 degrees Fahrenheit to as high as -10 degrees Fahrenheit and observed hydrogen-hydrogen atomic distances in the metal hydride, as small as 1.6 angstroms, compared to the 2.1 angstrom distances predicted for these metals. Computer simulations of the data proved conclusively that the unexpected spectral intensity occurs only when distances between hydrogen atoms are closer than 2.0 angstroms. The findings could possibly facilitate superconductivity at […]
Physicists make graphene discovery that could help develop superconductors
EurekAlert August 1, 2019 An international team of researchers (USA – Rutgers University, Japan) studied twisted bilayer graphene, created by superimposing two layers of graphene and slightly misaligning them. This creates a “twist angle” that results in a moiré pattern which changes rapidly when the twist angle changes and have a dramatic effect on the electronic properties of the material. This is because the moiré pattern slows down the electrons that conduct electricity in graphene and zip past each other at great speeds. At a twist angle of about 1.1 degrees – the so-called magic angle – the electrons come […]
Novel insulators with conducting edges
Eurekalert June 1, 2018 An international team of researchers (Switzerland, Spain, USA – Princeton University, Germany, France) has predicted a new class of topological insulators, called “higher-order topological insulators”, that have conducting properties on the edges of crystals rather than on their surface. The conducting edges are extraordinarily robust. If an imperfection gets in the way of the current, it simply flows around the impurity, if the crystal breaks, the new edges automatically conduct current and in theory electricity can be conducted without any dissipation. They have proposed tin telluride as the first compound to show these novel properties. The […]