Speakers


Klaus von Klitzing

Nobel Prize in Physics

1985

Counterintuitive as it may seem, few things are constant in the world of measurements. In the past, a local leader’s foot or hand and the weight of grains determined standards of length and mass respectively. While the world eventually agreed on a system of measures, some of these measures, too, have been unstable over time. 

In 1980, Dr Klaus von Klitzing discovered a true constant in nature. When he cooled semiconductor components to very low temperatures and applied very strong magnetic forces to them, their electrical resistance did not increase continuously as the magnetic field became stronger, but instead rose in a series of precise steps. 

In fact, further tests showed that this step-like electrical resistance can be found in any two dimensional electron system, meaning any system in which electrons are forced to move in an extremely thin layer. The electrical resistance at each step is also an integer fraction of a specific number, 25,812.807 ohms, which is now called the von Klitzing constant. 

For his discovery, which was named the Quantum Hall Effect, Dr von Klitzing was awarded the 1985 Nobel Prize in Physics. The prize committee noted that, “because of the extremely high precision in this effect, it may be used as a standard of electrical resistance” – a prediction that has come true. 

The Quantum Hall Effect is now used globally to calibrate electrical resistances. Dr von Klitzing’s work has also opened the research fields of topological phenomena in two-dimensional system and new quantum effects in low-dimensional electronic systems, which are crucial for computer science and new technologies. 

Furthermore, on 16 Nov 2018, members of the International Conference of Weights and Measures will vote on whether to update several basic units of measurements, including the ampere, kilogram and kelvin, based on fundamental constants of nature. If approved, the updated and fixed values will take effect from May 20, 2019, on World Metrology Day.

If this will happen, the vision of Max Planck becomes true who wrote in 1900: “With the help of fundamental constants, we have the possibility of establishing units that necessarily retain their significance for all cultures, even unearthly and non-human ones”. 

“The Quantum Hall Effect triggered this realisation,” said Dr von Klitzing, who is now director of the Low Dimensional Electron Systems department at the Max Planck Institute for Solid State Research in Stuttgart, Germany. 

Over the years, Dr von Klitzing has received numerous prizes and awards. Aside from the Nobel Prize, these include Honorary Doctorate Degrees in 14 countries and memberships in many science organisations, including the National Academy of Sciences of the United States of America, the Russian Academy of Sciences and the Chinese Academy of Science.