Klaus von Klitzing is a Nobel Prize-winning physicist who discovered that when the magnetic field is very strong and the temperature very low, electrical resistance in a two-dimensional conductor varies by discrete steps rather than smoothly and continuously. Now known as the integer quantum Hall effect, Klaus demonstrated experimentally the precise value of this stepped variance.
The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor. Klaus’s quantisation of Hall conductance enables scientists to realize the ohm, the standard unit of electrical resistance, with far greater precision. It also opened the possibility for the introduction of a new international system of units based on constants of nature.
The von Klitzing constant, RK, equivalent to almost 25,812.807 ohms, is named in Klaus’s honour. Klaus was awarded the 1985 Nobel Prize in Physics for his discovery of the quantized Hall effect. Klaus’s experiment is one of a very small number of cases where a fundamental constant can be measured directly with high precision.
Interest and expertise
Low dimensional electron systems, quantum Hall effect