Did You Ever Wonder How Electrons Move Through Exotic Crystals?

Eli Rotenberg studies a metal alloy that until recently scientists believed couldn't exist. To do so, he uses light rays one billion times brighter than the sun. And he visualizes his findings using powerful computer programs that portray how electrons move within the alloy.

Electron movement in quasicrystals Quasicrystal structure
The movement of electrons (left) observed in this quasicrystal can be correlated with the quasicrystal's structure (right).

Welcome to state-of-the-art material physics, where scientists use high-tech tools to explore strange substances with stranger names. Take Rotenberg, a staff scientist at Berkeley Lab's Advanced Light Source (ALS). He's interested in quasicrystals, which as the name implies are both like and unlike conventional crystals. Their in-between state has forced physicists to rethink the nature of crystalline structures, and they've given Rotenberg a unique chance to map the uncharted electronic properties of a little-understood substance. He aims extremely high-energy x-ray photons at a tiny quasicrystal sample, and uses a spectrometer to record the electrons that are knocked out. The momentum and direction of these electrons paint a detailed picture of the inner-workings of the quasicrystal.

"It's like determining what a violin looks like by only hearing the music it makes," Rotenberg says. "A violin and piano can both play a C note, but you can differentiate the two instruments because each has a different frequency. The same holds true for an electron's momentum -- it can tell us so much about the properties of different solids."

If this sounds complicated, you're right. No one grasps this stuff overnight; it takes years of work and cutting edge technology.

"And the tools we have at Berkeley Lab's ALS have given me a whole new vision of materials' properties," says Rotenberg.

How does someone land a job firing photons at exotic metals at Berkeley Lab? A little luck and a lot of hard work, according to Rotenberg. In high school, he found himself drawn to physics rather than biology and chemistry. In college, he majored in applied and engineering physics, and became very interested in learning how to develop experiments. Although he was enrolled in an engineering program, he gravitated more toward fundamental physics courses than real-world applications. By the time he graduated, he thought of himself as more of a physicist than an engineer, but he still had much to learn.

He went on to earn his Ph.D. in solid-state physics from UC Berkeley. Originally, he planned to work for a private lab such as those operated by IBM and AT&T, but these labs were devoted more to applied physics than basic science. So Berkeley Lab, an institution with a long history of fundamental physics research, became the obvious choice. A few years later, while killing time at a physics conference, he wandered into a room in which a researcher was discussing quasicrystals -- and Rotenberg immediately knew he wanted to analyze these strange structures.

More about Eli Rotenberg's research

Did You Ever Wonder Web Site

Ernest Orlando Lawrence Berkeley National Laboratory