Dancing electrons could open way to new devices

July 26th, 2008 - 5:01 pm ICT by IANS  


Washington, July 26 (IANS) Researchers have discovered a new way that electrons behave in materials, which could spur the development of futuristic electronic devices. A team led by N. Phuan Ong, professor of physics at Princeton University, has shown that electrons in an element like bismuth display a highly unusual pattern - a dance of sorts - when subjected to a powerful magnetic field at ultra-low temperatures.

Normally, electrons in bismuth come in three different varieties. But in this experiment, electrons in the magnetised, super-cold sample simultaneously assumed the identity of all three classes of electrons, following a strict choreography that could only stem, they say, from the strange rules of quantum physics.

Quantum mechanics governs the behaviour of objects in the microscopic world. The experiment documented the first “phase transition” - a term used to describe an abrupt change in the behaviour of a material - ever observed in a Group V element, one of the categories in chemistry’s periodic table.

“If you can imagine, it’s as if we were looking at passengers scrambling through Grand Central Station in New York, watching them run in different directions. All of a sudden, the whistle blows and we see them run to the same train. This is a simple example of a sudden transition to collective behaviour,” Ong said.

Although the maximum speed of electrons in bismuth is small compared with photons moving at the speed of light, the electrons mimic accurately the behaviour of elementary particles accelerated to very high speeds.

In bismuth, this “relativistic” property makes them likely candidates for the quantum behaviour, the scientists observed.

“This is exciting because this was predicted, but never shown before, and it may eventually lead to new paradigms in computing and electronics,” said Thomas Rieker, programme director at the National Science Foundation.

“In the quest to develop ever smaller and faster transistors, physicists and engineers are attempting to harness the quantum behaviour of electrons,” Ong said.

These findings were published on Friday in Science.

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