Contact: Bob Nelson (212) 854-6580 rjn2@columbia.edu |
For immediate release October 13, 1998 |
Horst Stormer, professor of physics and applied physics at Columbia University and adjunct director of physical sciences Bell Laboratories' Physical Science Division, a unit of Lucent Technologies Corp. in Murray Hill, N.J., will share the 1998 Nobel Prize in Physics for the discovery of bizarre motions of electrons in thin layers of semiconductors. Professor Stormer, a resident of Manhattan who is teaching an undergraduate course this term at Columbia, was honored with Daniel Tsui, a professor at Princeton University, for discovering a phenomenon known as the fractional quantum Hall effect, and with Robert B. Laughlin, a professor at Stanford University, for devising a theoretical explanation of this phenomenon. "I had no idea this was coming," Professor Stormer said at a Nobel reception held Oct. 13 in the Faculty Room of Columbia's Low Memorial Library. "Some people have premonitions; I had none." He added: "One German radio reporter asked me how it feels to become part of the same lineage as Einstein and Heisenberg. Let's not joke - I am not in the same league as Einstein and Heisenberg. "While I made this discovery at Lucent, I came to Columbia to help bridge the differences between industry and academia. I think we are succeeding." The research may eventually help create improved electronic devices such as computer chips or optoelectronic devices such as solid-state lasers. These structures, only a few hundred atoms across, are of immense technological importance because they will be capable of faster switching speeds and can be used to construct higher-density computer memories than is now possible. The Royal Swedish Academy of Sciences cited the trio "for their discovery of a new form of quantum fluid with fractionally charged excitations." They will share the $978,000 prize to be presented Dec. 10 in Stockholm. Professor Stormer holds joint appointments in Columbia's Graduate School of Arts and Sciences and the Fu Foundation School of Engineering and Applied Science. The award marks the 59th Nobel to a former or current Columbia faculty member or alumnus, and the fourth at the Fu Foundation School. Five Nobelists are currently on Columbia's faculty, four of them in physics. "Everyone at Columbia is of course thrilled to hear that the Nobel committee has recognized Horst Stormer's magnificent achievement," said George Rupp, president of the University. "It is certainly satisfying that such elegant basic science receives the acclaim it deserves." Professors Stormer and Tsui discovered the fractional quantum Hall effect in 1982 while both were Bell Laboratories researchers. The phenomenon occurs in a thin sheet of electrons inside a semiconductor, not unlike the electron sheet in a modern-day transistor. At temperatures that approach absolute zero and in strong magnetic fields, the electron appears to break up into three identical pieces, each with a fractional charge. However, this perplexing observation takes place not because the electron disintegrates, but because the motion of many electrons together generate unusual particle-like behavior in their midst. Such electrons can be made to travel as waves in quantum wires, and can be bound into new, artificial atoms called quantum dots. They can even enter superfluid states where they seem to move without friction or resistance. Within a year, Professor Laughlin, then also at Bell Labs, explained their result, showing that electrons in powerful magnetic fields can condense to form quantum fluids, similar to the superfluids that occur in superconductors and liquid helium. The discovery has opened up a new realm of scientific inquiry, the Nobel committee said, because "events in a drop of quantum fluid can afford more profound insights into the inner structure and dynamics of matter." Under these special conditions of low temperature and intense magnetic fields, current-carrying electrons do not move in all three spatial dimensions throughout the material but are confined to an extremely thin two-dimensional layer or one-dimensional line only a few hundred atoms thick. Electrons can be so confined by building up the semiconductor material in layers in such a way that one layer is different from the rest. This special layer provides a small attraction to the electrons as they move through the material. As the temperature is lowered, moving electrons have less energy and tend to occupy only quantum states located very near the special layer, finally abandoning all other quantum states at temperatures near absolute zero. Electrons forced to move in such confined structures display new, unexpected behavior, especially if a very intense magnetic field is applied. For example, such confined electrons display a new sort of electrical resistance that is precisely quantized into steps. This strange behavior implies that the fundamental current carriers are no longer individual electrons but instead electrons that as a group carry precisely a third or a fifth of the normal electronic charge. Professor Stormer, along with Professor Tsui at Princeton and Arthur Gossard of the University of California, Santa Barbara, were the first to observe this effect, called the fractional quantum Hall effect. "Understanding these bizarre properties has been a major success of condensed matter theory during the past decade," Professor Stormer said, prior to learning news of the Nobel Prize. "The fractional quantum Hall effect is very important for our understanding of many-particle physics, introducing as it does new ideas that may well have an important future effect on other areas of science. "While these new phenomena may not directly affect device technology, the structures we use in these experiments are essentially the same as those being used in high-performance current amplifiers." For example, the same two-dimensional system in which Professor Stūrmer has unraveled this counterintuitive behavior of electrons is the central component of a metal-oxide semiconductor field-effect transistor, or MOSFET, in which an input signal can control electrical current through the same two- dimensional electron system, called a channel; the device is central to thesemiconductor industry. And the identical materials that are being used in Professor Stormer's studies are also used to make high electron mobility transistors, or HEMTs. Such transistors are used as highly-sensitive gatekeepers in many of the new high-frequency, 2-gigahertz cellular phones. More recently, he has turned to the investigation of yet lower-dimensional systems, such as quantum wires embedded in semiconductor materials, where electrons are free to move only back and forth along a line. In such wires, electrons reveal their wave-like nature and travel like light waves down a glass fiber. Physicists believe that by adding mirrors to the ends of the wires, the quantum states of the electrons can be excited, creating a new, very narrow- frequency type of laser. They are also studying quantum dots, fully confined, zero- dimensional systems that act like artificial atoms. Professor Stūrmer, born in Frankfurt in 1949, earned his undergraduate and master's degrees in physics from Goethe University in Frankfurt and a Ph.D. in physics from the University of Stuttgart in 1977. He conducted his thesis research at the Max-Planck-Institut's High Field Magnet Laboratory in Grenoble, France. He joined AT&T Bell Laboratories in Murray Hill, N.J., became head of electronic and optical properties of solid research in 1983, and was appointed director of physical sciences in 1992. He accepted a joint appointment in Columbia's Department of Physics and the Department of Applied Physics and Applied Mathematics effective January 1. Professor Stormer won the American Physical Society's prestigious Oliver E. Buckley Prize in Condensed Matter Physics in 1984. He was awarded the Franklin Institute Medal in Physics with Professors Tsui and Laughlin, for the same work that won the Nobel, on April 30 in Philadelphia. He is a fellow of the American Physical Society and of the American Academy of Arts and Sciences. This document is available at http://www.columbia.edu/cu/pr/. Working press may receive science and technology press releases via e-mail by sending a message to rjn2@columbia.edu. 10.13.98 19,411