"The most stable form of trilayer graphene is ABA, which behaves like a metal," Lau explained. "Amazingly, if we simply shift the entire topmost layer by the distance of a single atom, the trilayer now with ABC or rhombohedral stacking becomes insulating. Why this happens is not clear as yet. It could be induced by electronic interactions. We eagerly await an explanation from theorists!"
Her lab used Raman spectroscopy to examine the graphene devices' stacking orders. Next the lab plans to investigate the nature of the insulating state in ABC-stacked graphene. In this kind of stacked graphene, they also plan to study the band gap a range in energy, critical for digital applications, in which no electrons can exist.
"The presence of the gap in ABC-stacked graphene that arises, we believe, from enhanced electronic interactions is interesting since it is not expected from theoretical calculations," Lau said. "Understanding this gap is particularly important for the major challenge of band gap engineering in graphene electronics."
Besides graphene, Lau studies nanowires and carbon nanotubes. Her research has helped physicists gain fundamental understanding of how atoms and electrons behave when they are ruled by quantum mechanics. Her lab studies novel electrical properties that arise from the quantum confinement of atoms and charges to nanoscale systems. Her research team has shown that graphene can act as an atomic-scale billiard table, with electric charges acting as billiard balls.
Her other research interests include superconductivity, thermal management and electronic transport in nanostructures, and engineering new classes of nanoscale devices.
An educational component of Lau's research effort is the active involvement of high school, undergraduate, and graduate students
|Contact: Iqbal Pittalwala|
University of California - Riverside