LSU physicists make major discovery, published in 'Nature'

An article written by two LSU researchers about their breakthrough discovery in the field of physics was published in the Jan. 11 issue of Nature magazine – one of the world's most prestigious scientific journals.

The article, titled "Quantum metallicity in a two-dimensional insulator," detailed significant new findings by professor Philip W. Adams and postdoctoral researcher Vladimir Y. Butko of the LSU Department of Physics and Astronomy.

The pair have been working to find out why metals stop being good conductors of electricity after reaching a certain thinness. Adams said many scientists have been trying to research this question by vaporizing metals and allowing the vapors to settle on other surfaces as a thin film. Then, they try to test the film for conductivity. However, he said studies have been problematic because the vapors of most metals fall in droplets, creating a film that is granular, making testing difficult and inaccurate.

But Adams and Butko found that vaporized beryllium makes a smooth film that is perfect for testing the effects of thinness. They found that ultra-thin beryllium films do not conduct electricity very well, mainly because the electrons in the material do not flow well. However, when they applied a magnetic field to the film, its resistance to conductivity dramatically decreased. The more the researchers increased the magnetic field, the more the beryllium's resistance fell, until finally, the resistance stabilized at what is known to physicists as the "quantum resistance."

The researchers said that when a magnetic field was applied, the metal film always found its way back to the same resistance. They believe that all metals react the same way and that this behavior was never previously observed because the granular films of other metals were so difficult to test. The key to this theory is that beryllium is not even magnetic, so the fact that a magnetic field would so drastically change the conductivity of that metal is a great surprise.

Adams said this discovery is significant because it shows that there is a universal standard for limiting a metal film's resistance to conductivity and that the standard is based on the behavior of electrons in metals when exposed to magnetic fields. Adams said these findings are important enough to be included in textbooks in the future.

Adams, who has been a member of the LSU faculty since 1988, said the discovery has gained much attention for his postdoctoral researcher. He said that Butko, who is also a faculty member at the Ioffe Physical Technical Institute in St. Petersburg, Russia, has received numerous offers of employment since the article was published in Nature. He has been offered postdoctoral research positions at Cornell University and the University of Chicago and is interviewing for faculty positions at several research universities in the U.S.

Published weekly in London, Nature contains only a handful of research articles and letters in each issue. It covers all areas of science, with only a couple of items dealing with physics and materials science each week. Several LSU researchers have been published in Nature in the past year, including associate professor John DiTusa, also of the Department of Physics and Astronomy.

Contact Kristine Calongne
LSU News Service
225-578-5985
[email protected]

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