| Citation | Klaus von Klitzing won the Nobel Prize for Physics in 1985 for his discovery of the Quantum Hall Effect. By measuring the electrical properties of a silicon field effect transistor at low temperatures and high magnetic field, he showed that the Hall conductivity of a two-dimensional electron gas is quantised in units of e2/h, where e is the electron charge and h is Planck's constant. His discovery led to the use of the Hall effect as the new international standard of electrical resistance. This standard value now bears his name. His seminal research was crucial to the discovery of the fractional quantum Hall effect for which Laughlin, Störmer and Tsui were jointly awarded the Nobel Prize in 1998. Quantum Hall effect physics remains a very active field of research with, on average, one new publication appearing every day. The quantum Hall effect has relevance beyond semiconductor physics; eg work has recently been undertaken to search for changes in the von Klitzing constant on a cosmological timescale; the quantum Hall system has also proved relevant to black holes and other exotic systems. Von Klitzing and his Stuttgart team continue to make major advances in the physics of nanostructures and in molecular electronics. Von Klitzing is an active international ambassador of physics, and visits the UK frequently. His first postdoctoral appointment was at Oxford in 1975, funded by the Royal Society's European Science Exchange Programme. |