Chance effect of lab's fluorescent lights leads to discovery

Monday, October 12, 2015

An accidental discovery of a "quantum Etch-a-Sketch" that may lead to the next generation of advanced computers and quantum microchips has been made by team of scientists from Penn State University and the University of Chicago. The researchers accidentally discovered a new way of using beams of light to draw and erase quantum-mechanical circuits on topological insulators, a unique class of materials with intriguing electronic properties.

The research, led by Nitin Samarth, professor and Downsbrough Head of Physics at Penn State, and David D. Awschalom, Liew Family Professor and deputy director in the Institute of Molecular Engineering at the University of Chicago, was published in the October 9 issue of Science Advances, an online journal of the American Association for the Advancement of Science.

The new technique is more flexible than advanced nanofabrication facilities based on chemical processing because it allows for rewritable "optical fabrication" of the topological insulators. "This observation came as a complete surprise," Awschalom said. "It's one of those rare moments in experimental science where a seemingly random event -- turning on the room lights -- generated unexpected effects with potentially important impacts in science and technology."

The electrons in topological insulators have unique quantum properties that many scientists believe will be useful for developing spin-based electronics and quantum computers. However, making even the simplest experimental circuits with these materials has proved difficult because traditional semiconductor engineering techniques tend to destroy their fragile quantum properties. Even a brief exposure to air can reduce their quality.