Canadian physicists stumble upon new state of matter in a 'transistor'

Tony Austin
Tuesday, 28 October 2008 08:30

Opinion and Analysis

The new state of matter, a quasi-three- dimensional electron crystal, is a material very much like those used in the fabrication of modern transistors.

The research was carried out by McGill University's Ultra-Low Temperature Condensed Matter Experiment Lab.

Two-dimensional electron crystals were discovered in the laboratory in the 1990s, and were predicted as far back as 1934 by renowned Hungarian physicist Eugene Wigner.

“Picture a sandwich, and the ham in the middle is your electrons,” explained lab director Dr. Guillaume Gervais.

“In a 2D electron crystal, the electrons are squeezed between two materials and they’re very two dimensional. They can move on a plane, like billiard balls on a pool table, but there’s no up and down motion. There’s a thickness, but they’re stuck.”

Until an accidental discovery during one of Gervais’ earliest ultra-low temperature experiments in 2005, however, no one predicted the existence of quasi-three-dimensional electron crystals.

“We decided to tweak the two-dimensionality by applying a very large magnetic field, using the largest magnet in the world at the Magnet Lab in Florida,” he said. “You only have access to it for about five days a year, and on the third day, something totally unexpected popped.”

His “pop” was the startling transformation of a two-dimensional electron system inside the semiconducting material into a quasi-three-dimensional system, something existing theory did not predict.

“It’s actually not quite 3-D, it’s an in-between state, a totally new phenomenon,” he said. “This is the kind of thing the theoreticians love. Now they’re scratching their heads and trying to fine-tune their models.”

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