Daniel Chee Tsui
Tsui, Daniel Chee (1939-) is a Chinese-born American physicist who shared the 1998 Nobel Prize in physics with American scientist Robert B. Laughlin and German scientist Horst Ludwig Stormer. Tsui and Stormer discovered the fractional quantum Hall effect in 1982.
Tsui was born in 1939 in Henan Province in central China. He came to the United States in 1958 to attend Augustana College, in Rock Island, Illinois, and received a B.A. degree in 1961. He then entered graduate school at the University of Chicago, where he earned both a master's degree and a Ph.D. degree in 1967.
In 1968, Tsui went to work for Bell Labs in Murray Hill, New Jersey. There, he and Stormer began studying the quantum Hall effect, which was discovered by American physicist Edwin Hall in 1879. Hall discovered that when a gold plate is placed in a magnetic field at right angles to an electric current at its surface, the current flowing along the plate drops at right angles. This phenomenon is useful in determining the density of charge carriers in conductors and semiconductors. In 1977, German physicist Klaus von Klitzing demonstrated that as a magnetic field intensifies, the Hall effect does not increase in a linear fashion, but in steps according to the strength of the field.
In their experiments, Tsui and Stormer joined two semiconductors, gallium arsenide and gallium aluminum arsenide, in order to trap electrons on a two-dimensional plane. Next, the researchers cooled the electron trap down to a tenth of a degree above absolute zero (-273.15 °C) and placed it in a magnetic field one million times the strength of the earth's. The two scientists discovered that lower temperatures and higher field strengths resulted in even more steps than von Klitzing had discovered, and were divided by different fractions, thus the term “fractional quantum Hall effect.” Laughlin explained their results in 1983.