Phys.org July 8, 2021 The grand challenge in superconductivity research and development is no longer restricted to further increasing the superconducting transition temperature under extreme conditions and must now include concentrated efforts to lower, and better yet remove, the applied pressure required. An international team of researchers (USA – Houston University, Rice University, China) has shown such a possibility in the pure and doped high-temperature superconductor FeSe by retaining, at ambient pressure via pressure quenching, its Tc up to 37 K and other pressure-induced phases. They observed that some phases remain stable without pressure at up to 300 K and […]
Category Archives: Superconductivity
Superconductivity, high critical temperature found in 2D semimetal tungsten nitride
Phys.org May 5, 2021 Researchers in Switzerland used first-principles calculations to identify intrinsic superconductivity in monolayer W2N3, a material that has recently been identified as being easily exfoliable from a layered hexagonal-W2N3 bulk by calculations, a theory also supported by experimental evidence. They found a critical temperature of 21 K, that is, just above liquid hydrogen and a record-high transition temperature for a conventional phonon-mediated 2D superconductor. According to the researchers the material could be doped such that currently unoccupied helical edge states 0.5 eV above the Fermi level become filled, even while superconductivity persists making W2N3 a viable candidate […]
New 2D superconductor forms at higher temperatures than ever before
Phys.org April 27, 2021 The distinctive electronic structure found at interfaces between materials can allow unconventional quantum states to emerge. An international team of researchers (USA – Argonne National Laboratory, University of Illinois, China) has discovered superconductivity in electron gases formed at interfaces between (111)-oriented KTaO3 and insulating overlayers of either EuO or LaAlO3. The superconducting transition temperature, as high as 2.2 kelvin, is about one order of magnitude higher than that of the LaAlO3/SrTiO3 system. Similar electron gases at KTaO3 (001) interfaces remain normal down to 25 millikelvin. The critical field and current-voltage measurements indicated that the superconductivity is […]
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 […]
Superconductivity with a twist explained
Phys.org September 29, 2020 An international team of researchers (Switzerland, Spain, the Netherlands, Italy, Japan) has shown that the interplay between the two hexagonal carbon lattices, slightly twisted, causes a much larger hexagonal moiré pattern to emerge. By creating this new periodicity, the interaction between the electrons changes, yielding “slow” electrons enabling superconductivity. At a temperature of 1.7 Kelvin, twisted bilayer graphene conducts electricity without resistance. The researchers have finally confirmed the mechanism behind these fascinating new superconductors…read more. TECHNICAL ARTICLE
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 […]
Scientists created an ‘impossible’ superconducting compound
Phys.org March 3, 2020 An international team of researchers (China, Russia) successfully synthesized praseodymium superhydrides (PrHg) and showed the emergence of a possible superconducting transition (Tc) below 9 K and Tc dependent on the applied magnetic field. Theoretical calculations indicated that magnetic order and likely superconductivity coexist in a narrow range of pressures in the PrHg sample, which may contribute to its low superconducting temperature. The results highlight the intimate connections between hydrogenic sublattices, density of states, magnetism, and superconductivity in Pr-based superhydrides…read more. Open Access TECHNICAL ARTICLE
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 […]
Suspended layers make a special superconductor
Phys.org November 5, 2019 Researchers in the Netherlands created a suspended double layer of molybdenum disulfide with an ionic liquid on both sides that can be used to create an electric field across the bilayer. In the individual monolayer, such a field will be asymmetric, with positive ions on one side and negative charges induced on the other. However, in the bilayer, they could have the same amount of charge induced at both monolayers, creating a symmetrical system. The electric field that was thus created could be used to switch superconductivity on and off. This means that a superconducting transistor […]
Scientists finally find superconductivity in place they have been looking for decades
Phys.org September 26, 2019 The biggest obstacle to making superconductors operate at higher temperatures and making superconductivity more robust has been the lack of a model. High-temperature superconductors are quantum materials, where electrons cooperate to produce unexpected properties. A team of researchers in the US (Stanford University, SLAC National Accelerator Laboratory) created a virtual version of a cuprate on a square lattice, like a wire fence with square holes where each virtual atom can accommodate at most two electrons that are free to jump or hop—either to their immediate neighbors on the square lattice or diagonally across each square. When […]