Von Klitzing, Klaus (1943-…), a German physicist, carried out research into the behavior of electric currents in semiconducting materials in magnetic fields (regions where magnetic forces can be felt) at low temperatures. Semiconducting materials, also called semiconductors, are substances that conduct electric current better than an insulator, but not as well as a conductor (see Semiconductor ). Von Klitzing provided an extremely accurate method of measuring electrical resistance (the opposition of a material to an electric current) and opened up a flourishing new area of research. He was awarded the Nobel Prize for physics in 1985.
The new method of measurement was made possible by von Klitzing’s studies of the Hall effect, discovered by American physicist Edwin H. Hall in 1879. Hall found that when a magnetic field is applied to a conductor, such as a wire or a piece of semiconducting material, a voltage called the Hall voltage develops sideways across the conductor. The Hall voltage increases consistently with the strength of the applied magnetic field and the current. In 1977, von Klitzing presented a paper showing that at low temperatures the Hall voltage increases in steps. However, it was not until 1980 that he realized that such jumps could only be explained by quantum mechanics, a field of physics dealing with the forces inside an atom. See Hall effect ; Quantum mechanics .
The quantum Hall effect, as it became called, provides a way of making extremely accurate measurements of resistance. A laboratory anywhere in the world can now produce a standard resistance of precisely known value.
Klaus von Klitzing was born on June 28, 1943, in Schroda, in what was then German-occupied Poland, and is now called Sroda Wielkopolksa in the province of Poznan, Poland. He received his Ph.D. from Wurzburg University, Germany. He gained his doctorate for his work on the electrical effects of strong magnetic fields on the element tellurium. He remained at Wurzburg until 1980, with periods of research at the Clarendon Laboratory, Oxford, in the United Kingdom, and the High Magnetic Field Laboratory in Grenoble, France. From 1980 to 1984, von Klitzing was a professor at the Technical University, Munich. In 1985, he became director of the Max Planck Institute for Solid-State Research in Stuttgart, Germany.
