|Klaus von Klitzing|
OK, today we have a topic that is a little bit complicated to explain, at least to us non-physicists. Let's start with the 'traditional' Hall-effect. The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current. It was already discovered in the 19th century by American physicist Edwin Herbert Hall. As a young doctoral student in 1879 Edwin H. Hall discovered an unexpected phenomenon. He found that if a thin gold plate is placed in a magnetic field at right angles to its surface an electric current flowing along the plate can cause a potential drop at right angles both to the current and the magnetic field (see figure 1). Termed the Hall effect, this takes place because electrically charged particles (in this case electrons) moving in a magnetic field are influenced by a force, called the Lorentz force, and deflect laterally. The Hall effect can be used to determine the density of charge carriers (negative electrons or positive holes) in conductors and semi-conductors, and has become a standard tool in physics laboratories the world over.
At yovisto you can learn more about the Quantum Hall Effect, explained by Nobel Laureate Prof. Klaus von Klitzing himself, being held at the Danish Royal Academy.
References and Further Reading:
- 1998 Press Release of the Swedish Academy of Sciences: Electrons in new Disguise
- Klaus von Klitzing: The Quantized Hall Effect, Nobel lecture, 1985
- Homepage of Klaus von Klitzings Research Group at the Max-Planck-Institute for Solid State Research
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