A Grand Unifying Theory of Superconductivity

Scientists have been puzzled for many years by the enigmatic and complex array of behaviours exhibited by electrons during high-temperature superconductivity experiments on copper-, iron- and heavy fermion materials. Superconductivity is a phenomenon observed when a material is cooled below a critical point and shows no electrical resistance, and the absence of a magnetic field. These materials are key for energy-saving appliances as it means that no energy is lost from these systems.

Scientists have been trying to discern a unifying theory regarding this phenomenon, as although different conditions are favoured in different materials, the fact superconductivity occurs across a range of materials suggests some common state or property. Recently, through the combination of experiments (performed by Seamus Davis) and theories (postulated by Dung-Hai Lee) the similarities and differences in electron behavior between these materials have been identified, and the driving forces behind these interactions.  There are many different types of ‘intertwined’ electron phases which can occur that can either promote the superconductivity property or hinder it.

The theory outlined in a recent journal article in the Proceedings of the National Academy of Science suggests that different materials have characteristic arrangements of electrons, known as ‘Fermi surface topology’ and that the electrons can align in magnetic interactions of differing strengths. Basically – underneath the complex alignment of electrons (that varies depending on the conditions) is a metal phase that can be described simply.

So far the theory has produced all observed phases seen within known superconductors however, the next step will be to predict the potential superconducting properties of different – and possibly even new materials – and test them experimentally.

http://www.bnl.gov/newsroom/news.php?a=11580