Phys.org March 22, 2021 Previously a team of researchers in the US (University of Rochester, SUNY Buffalo, University of Nevada) had shown that when a hydrogen-rich compound was squeezed to 267 GPa it became superconductive. In the new research the same team combined hydrogen with yttrium instead of carbon and sulfur greatly reducing the pressure. Two diamond anvils used to create the pressure were placed slightly apart with hydron gas and a sample of yttrium in its solid state between them. To prevent oxidation of the yttrium a sheet of palladium was placed between them. It also served as a […]
Tag Archives: Superconductivity
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 […]
Scientists manipulate magnets at the atomic scale
Science Daily February 12, 2021 An international team of researchers (the Netherlands, Ukraine, Russia, Belgium, UK) shows that light-driven phonons can be utilized to coherently manipulate macroscopic magnetic states. Intense mid-infrared electric field pulses tuned to resonance with a phonon mode of the archetypical antiferromagnet DyFeO3 induce ultrafast and long-living changes of the fundamental exchange interaction between rare-earth orbitals and transition metal spins. Non-thermal lattice control of the magnetic exchange, which defines the stability of the macroscopic magnetic state, allows picosecond coherent switching between competing antiferromagnetic and weakly ferromagnetic spin orders. The discovery emphasizes the potential of resonant phonon excitation […]
Acoustic plasmons found in hole-doped cuprate superconductors
Phys.org December 14, 2020 An international team of researchers (France, USA – University of Illinois, Stanford University, Binghamton University, SLAC National Accelerator Laboratory, University of Maryland, Italy, UK, Argentina, Japan) has confirmed the presence of acoustic plasmons in p-type cuprate superconductors and that they are primarily associated with the oxygen atoms. It seems that the collective charge excitations have strong preference in space, despite the fact that the charges associated with Cu and O atoms are strongly hybridized with each other. Understanding this may help us to clarify the ground state of the cuprate superconductors. This opens new opportunities to […]
Ultra-thin designer materials unlock quantum phenomena
Science Daily December 17, 2020 Exotic states such as topological insulators, superconductors and quantum spin liquids are often challenging or impossible to create in a single material. The problem can be circumvented by deliberately selecting the combination of materials in heterostructures so that the desired physics emerges from interactions between the different components. An international team of researchers (Finland, Poland, Japan) used molecular-beam epitaxy to grow 2D islands of ferromagnetic chromium tribromide on superconducting niobium diselenide. They used low-temperature scanning tunneling microscopy and spectroscopy to reveal the signatures of one-dimensional Majorana edge modes. The fabricated 2D van der Waals heterostructure […]
Superconductors are super resilient to magnetic fields
Phys.org September 7, 2020 It was once assumed that the superconducting-to-normal transition caused by a magnetic field could not be reversed easily. However, it has been known for a long time from experiments that, if you remove the magnetic field, a current-carrying superconductor can, in fact, be returned to its previous state without loss of energy. Researchers in Japan proposed a new explanation for this phenomenon. In the superconducting state, electrons pair up and move in sync, but the true cause of this synchronized motion is due to Berry connection, characterized by the topological quantum number. It is an integer […]
‘Tantalizing’ clues about why a mysterious material switches from conductor to insulator
Nanowerk May 18, 2020 Researchers in Japan created crystals of tantalum disulfide and then cleaved the crystals in a vacuum to reveal ultra-clean surfaces which they examined, at a temperature close to absolute zero. Using quantum tunneling they studied the degree of conducting behavior of the material. The results showed that there was indeed a stacking of layers which effectively arranged them into pairs. Sometimes the crystals cleaved between the pairs of layers, and sometimes through a pair, breaking it. They performed spectroscopy on both the paired and unpaired layers and found that even the unpaired ones are insulating, leaving […]
Manipulating atoms to make better superconductors
Science Daily March 3, 2020 The creation of collective behavior is the fundamental building block from which superconductivity emerges. A team of researchers in the US (University of Illinois at Chicago, SLAC National Accelerator Laboratory, Stanford University) had theoretically predicted in a Kondo droplet, for certain distances between the cobalt atoms, the nanoscopic system should start to exhibit collective behavior, while for other distances, it should not. They confirmed the predictions by experiments that showed that collective behavior appears in Kondo droplets containing as little as 37 cobalt atoms. It allows us to move one step closer to developing the […]
Electronic map reveals ‘rules of the road’ in superconductor
Science Daily December 6, 2019 An international team of researchers (USA – Rice University, UC Berkeley, SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory, Stanford University, China) has developed a band structure map from the data gathered from measurements of a single crystal of iron selenide as it was cooled to the point of superconductivity. They are making observations of different types of exotic materials and figuring out the quantum mechanical rules that govern electron behavior in those materials. The electronic structure helps deciding if a material will be a good conductor or a good insulator or a superconductor…read more. […]
Finding the ‘magic angle’ to create a new superconductor
Science Daily October 2, 2019 Earlier this year, scientists at MIT reported that graphene could become a superconductor if one piece of graphene were laid on top of another piece and the layers twisted to a specific angle , they called “the magic angle” of between 1 degree and 1.2 degrees. Now an international team of researchers (USA – Ohio State University, TT Dallas, Japan) found that graphene layers still superconducted at a smaller angle, around 0.9 degrees. It is a small distinction, but the findings provide a wealth of new information to help decipher the strongly correlated phenomena observed […]