An international team of researchers has uncovered the atomic mechanism behind high-temperature superconductors, a finding that could be revolutionary for super-efficient electrical power.
In a paper published in the journal Proceedings of the National Academy of Science, the researchers explain that certain copper oxide materials demonstrate superconductivity at higher temperatures than conventional superconductors, however, the mechanism behind this has remained unknown since their discovery in 1987.
To investigate this, the group developed two new microscopy techniques. The first of these measured the difference in energy between the copper and oxygen atom orbitals, as a function of their location. The second method measured the amplitude of the electron-pair wave function – the strength of the superconductivity – at every oxygen atom and at every copper atom.
“By visualizing the strength of the superconductivity as a function of differences between orbital energies, for the first time ever we were able to measure precisely the relationship required to validate or invalidate one of the leading theories of high-temperature superconductivity, at the atomic scale,” lead researcher Séamus Davis said in a media statement.
As predicted by the theory, the results showed a quantitative, inverse relationship between the charge-transfer energy difference between adjacent oxygen and copper atoms and the strength of the superconductivity.
According to the research team, this discovery could prove a historic step toward developing room-temperature superconductors. Ultimately, these could have far-reaching applications ranging from maglev trains, nuclear fusion reactors, quantum computers, and high-energy particle accelerators, not to mention super-efficient energy transfer and storage.
The scientists also explain that in superconductor materials, electrical resistance is minimized because the electrons that carry the current are bound together in stable ‘Cooper pairs.’
In low-temperature superconductors, Cooper pairs are held together by thermal vibrations, but at higher temperatures, these become too unstable. These new results demonstrate that, in high-temperature superconductors, the Cooper pairs are instead held together by magnetic interactions, with the electron pairs binding together via a quantum mechanical communication through the intervening oxygen atom.
“This has been one of the Holy Grails of problems in physics research for nearly 40 years,” Davis said. “Many people believe that cheap, readily available room-temperature superconductors would be as revolutionary for the human civilization as the introduction of electricity itself.”