Year & Category
1985 Nobel Prize in Physics
“For the discovery of the quantized Hall effect”
At the time of the award he worked at
Max-Planck-Institut für Festkörperforschung, Stuttgart, Federal Republic of Germany
About his research
Klaus von Klitzing received the 1985 Nobel Prize in Physics for a discovery that has had a decisive impact on today’s measuring technology.
How can you measure electrical resistance? We now know how to do that very precisely thanks to Klaus von Klitzing. His discovery of the quantized Hall effect led to an internationally binding yardstick.
Extreme magnetic forces
If a metal conductor with electricity flowing through it is placed in a magnetic field perpendicular to the layer of electrons, you can measure an electric charge in the layer vertical to the direction of current. This Hall effect, which is named after the American physicist Edwin Herbert Hall, had already been known for roughly one hundred years before Klaus von Klitzing increased our understanding of the phenomenon. At the High Magnetic Field Laboratory in Grenoble, France, von Klitzing applied extreme magnetic forces to semiconductor components and cooled them to temperatures approaching absolute zero.
Furthering semiconductor research
Contrary to what had generally been assumed, the resistance did not increase continuously as the magnetic field became stronger. Instead it rose in a series of steps, reaching levels where it remained at the same value for a certain time. The quantized Hall effect was discovered. It is also possible to represent these different steps with great precision: as integer fractions of what came to be known as the von Klitzing constant (25,812.807 ohms). Since 1 January 1990 this has been considered the internationally binding measure for determining electrical resistance. Von Klitzing’s work also gave a significant boost to research into semiconductors far below the scale of today’s microelectronics. Klaus von Klitzing is still investigating the potential possibilities at the Max Planck Institute for Solid State Research in Stuttgart, which has left a major mark on international semiconductor research in recent decades.