This year’s laureates used advanced mathematical methods to study unusual phases or states of matter, such as superconductors, superfluids or thin magnetic films.
In the early 1970s, Michael Kosterlitz and David Thouless overturned the then current theory that superconductivity or suprafluidity could not occur in thin layers. They demonstrated that superconductivity could occur at low temperatures and also explained the mechanism, phase transition, that makes superconductivity disappear at higher temperatures.
In the 1980s, Thouless was able to explain a previous experiment with thin electrically conducting layers in which conductance was precisely measured as integer steps. At around the same time, Duncan Haldane discovered how topological concepts can be used to understand the properties of chains of small magnets found in some materials.
The three laureate’s work demonstrated that the idea of topology – the mathematical study of how surfaces can be deformed continuously and smoothly – could be used to predict the behaviour of solids.
Thouless, Kosterlitz and Haldane’s work has laid the foundations for new emerging fields, such as topological insulator materials in solid state physics. These are 3D materials that carry electricity on the surface but not in their interior. The materials have many 'spintronic applications' and heads of hard drives based on this technology are said to be currently used in industry.
In the future, topological materials could be used in new generations of electronics and superconductors, or in quantum computers.