Störmer, Horst Ludwig (1949-…), a German experimental physicist, shared the 1998 Nobel Prize for physics with American physicists Daniel Tsui and Robert Laughlin for work leading to the development of new theoretical concepts in many branches of modern physics. Störmer and Tsui carried out experiments in which it seemed that electrons—the particles making up electric currents—had been divided into parts. Laughlin provided a theoretical explanation for the phenomenon, which is called the fractional quantum Hall effect.
Störmer and Tsui discovered that electric currents behave in a strange way in a strong magnetic field. Electric currents in the semiconductor materials they were studying consist of negatively charged electrons and positive “holes.” Electrons are fundamental particles that have a negative charge. Positive holes are places where electrons are missing in the sea of electrons in the semiconductor, and they behave like positively charged particles. Semiconductors are the basic material of transistors, microchips, and many other components in modern electronic devices.
Störmer was born on April 6, 1949, in Frankfurt-am-Main. He received a Ph.D. degree from Stuttgart University. He was working at Bell Laboratories (then the research department of the Bell Telephone Company) in the United States at the time of his Nobel Prize winning research. He and Tsui made an electrical component that consisted of two kinds of semiconductor materials joined together. The materials that Störmer and Tsui used were gallium arsenide and gallium aluminum arsenide.
The effect that Störmer and Tsui were studying is called the quantum Hall effect. It was discovered by a German physicist, Klaus von Klitzing . The original Hall effect had been discovered in 1879 by the American physicist Edwin H. Hall. When a current flows in an electrical conductor through which a magnetic field passes, the electrons (or other carriers of charge) feel a force from the magnetic field that makes them pile up on one side of the conductor. The piling up of electrons causes a sideways voltage across the wire, called the Hall voltage. The Hall voltage increases as the applied magnetic field is increased.
Störmer and Tsui cooled their component to one-tenth of a degree above absolute zero and applied magnetic fields that were one million times as strong as Earth’s magnetic field and several times as strong as the fields von Klitzing had used. They were astonished to find that electrons were behaving as though they had split into pieces with only a fraction of their normal charge. Laughlin explained the effect as due to collective behavior on the part of the electrons. When electrons behave in this way, they are said to form a type of quantum fluid. A quantum fluid is superconducting—that is, it has no electrical resistance—and superfluid—that is, it flows perfectly freely.
Störmer had joined Bell Laboratories in 1992 and was supervisor of its Physical Research Laboratory, where he worked until 1998. In 1998, he became a professor at Columbia University in New York City.
