History
The integer quantization of the Hall conductance was originally predicted by Ando, Matsumoto, and Uemura in 1975, on the basis of an approximate calculation which they themselves did not believe to be true. Several workers subsequently observed the effect in experiments carried out on the inversion layer of MOSFETs. It was only in 1980 that Klaus von Klitzing, working with samples developed by Michael Pepper and Gerhard Dorda, made the unexpected discovery that the Hall conductivity was exactly quantized. For this finding, von Klitzing was awarded the 1985 Nobel Prize in Physics. The link between exact quantization and gauge invariance was subsequently found by Robert Laughlin. Most integer quantum Hall experiments are now performed on gallium arsenide heterostructures, although many other semiconductor materials can be used. In 2007, the integer quantum Hall effect was reported in graphene at temperatures as high as room temperature, and in the oxide ZnO-MgxZn1-xO.
Read more about this topic: Quantum Hall Effect
Famous quotes containing the word history:
“Culture, the acquainting ourselves with the best that has been known and said in the world, and thus with the history of the human spirit.”
—Matthew Arnold (18221888)
“Like their personal lives, womens history is fragmented, interrupted; a shadow history of human beings whose existence has been shaped by the efforts and the demands of others.”
—Elizabeth Janeway (b. 1913)
“Only the history of free peoples is worth our attention; the history of men under a despotism is merely a collection of anecdotes.”
—Sébastien-Roch Nicolas De Chamfort (17411794)