In the process of her doctoral work, initially focused on developing parallelized codes to understand and visualize the dynamics of solitons and vortices in BEC, Leung found her own kind of quantum coherence – a fellowship program that was just right for her.
“When I found the DOE CSGF, I thought: This is perfect for me. I love all of these things,” recalls Leung. The Fellowship requires participants to take science, applied math, and computer science courses, and Leung was particularly inspired by an algorithms course.
But it was the Fellowship practicum that let her really test her mettle as an emerging computational scientist.
During a workshop she attended on the computational tools at DOE’s Lawrence Berkeley National Lab, Leung met Dr. Andrew Canning, a staff scientist in Berkeley Lab’s Computational Research Division. She was intrigued by his work: Although also exploring computational methods for quantum systems, Dr. Canning models solid state systems. It’s a realm that offered a new challenge for Leung, one that she readily took on when offered the chance of a three-month practicum with Dr. Canning.
Leung’s practicum research was part of an ongoing collaboration between, among others, Dr. Canning and Dr. Z.Q. Qiu, a solid state physicist who holds a joint appointment with the Lab’s Materials Sciences Division and the Physics Department of the University of California at Berkeley. Dr. Qiu’s group is a world leader in the creation of very pure, nanoscale metallic films. These thin metal films (sometimes only several atoms thick) are ideal for studying quantum mechanical effects and are at the frontier of a new realm of materials engineering.
“In the past, people have designed materials to have specific mechanical properties, such as strength,” says Dr. Canning. “Now, because we can engineer at the atomic level, the idea is to design materials in which we can control the properties of individual electrons.”
Using Berkeley Lab’s IBM SP supercomputer, Leung modeled Dr. Qiu’s experiments conducted at the Lab’s Advanced Light Source, to understand the effect of the addition of a nanoscale nickel monolayer on quantum well states in copper. Quantum well states are an energy state in which an electron is sandwiched between two layers of atoms so that its motion is confined to a single dimension. They are thought to be responsible for the giant magneto resistance effect, the basis for the creation of very high density disk drives.
Leung and Canning’s simulations have already provided a more detailed physical understanding of the nickel-copper quantum well state experimental results, as well as confirming some of the theoretical models used by Dr. Qiu’s group.