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Klitzing, Klaus von

hall effect resistance field

(1943– ) German physicist: discovered the quantum Hall effect.

Von Klitzing was born in Schroda/Posen and studied at Braunschweig and Würzburg. He became a professor in 1980 at Munich, and in 1985 director of the Max Planck Institute, Stuttgart. In 1977 he presented a paper on two-dimensional electronic behaviour in which the quantum Hall effect can be clearly seen. However, few realized the significance of the measurements, and it was only when working one night at the high magnetic field laboratory in Grenoble in 1980 that von Klitzing appreciated what had occurred.

An electronic gas that is confined into a flat layer can be made by depositing a very thin layer of semiconductor upon a base material. Under a magnetic field electrons will perform circular orbits, with only particular energy states allowed (called levels). At certain values of the field the Landau levels become filled and the conductivity and resistivity fall to zero. Others had put forward a theory that the (Hall) resistance under such conditions should rise in units of h / e 2 ; von Klitzing demonstrated that the resistance did rise in steps and accurately obeyed this condition. He had discovered the quantum Hall effect (QHE), and for this won the 1985 Nobel Prize for physics.

The effect has caused new thinking on electrical conduction in high magnetic fields; and it has allowed resistance to be measured with exceptional accuracy.

Klug, Sir Aaron [next] [back] Klein (Hannah Golofsky), Anne

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