Horst L. Störmer
Born: 6 April 1949, Frankfurt-on-the-Main, West Germany (now Germany)
Affiliation at the time of the award: Columbia University, New York, NY, USA
Prize motivation: "for their discovery of a new form of quantum fluid with fractionally charged excitations."
Prize share: 1/3
The Hall effect refers to the fact that if an electrical current flows lengthwise through a metal band and a magnetic field is placed against the surface of the band at a right angle, a charge arises diagonally in the band. In interfaces in certain materials a quantum Hall effect occurs. Klaus von Klitzing discovered that changes in the magnetic field result in changes in what is known as Hall conductance that vary in steps of whole-number multiples of a constant. Subsequently, Horst Störmer and Daniel Tsui discovered in 1982 that there also are steps that represent fractions of the constant.