King's Fellow makes breakthrough in superconductor mystery
King's Fellow Suchitra Sebastian has just published a paper explaining what makes some materials superconductors at high temperatures. It is a problem that has puzzled scientists for 30 years.
Superconductors are materials that have no resistance to electric current. High temperature superconductors were discovered in the mid 1980s and have superconducting properties up to 38 Kelvin (-135º Celsius). Above that temperature, they offer resistance to current flowing through them.
Superconductors offer no resistance because their electrons travel in pairs. To understand what sticks the electrons together, we need to understand the electronic structure within which pairing occurs. Dr Sebastian and her team at the Cavendish Laboratory succeeded in describing the electronic structure of high temperature superconductors in the ‘normal' state within which electrons pair.
The research team took a copper-oxide superconducting material and applied a magnetic field high enough for it to lose its superconducting properties. They observed the electronic structure of the material in its non-superconducting state and found that the pockets of electrons developed with an unusual twisted structure in the non-superconducting state. Electrons must therefore pair within this structure to yield high temperature superconductivity.
The results have huge implications because now we can look for materials with similar properties, that we can make into new superconductors, perhaps ones that will work at higher temperatures. This is turn could have a massive impact on the transportation and storage of energy across the world, and the power consumption of everyday appliances (see the previous news story).
For a more extensive overview of the paper see the University research news.
Sebastian, Harrison, Balakirev, Altarawneh, Goddard, Liang, Bonn, Hardy & Lonzarich (2014) . Normal-state nodal electronic structure in underdoped high-Tc copper oxides. Nature.