Gang Seob “GS” Jung has known from the time he was in middle school that he was interested in science.
“I liked to calculate how things move. You could predict something. I felt like it was a game or a fun puzzle. It was interesting to imagine different initial conditions and guess how it was going to move,” he said. “I am still solving puzzles using computational modeling for science.”
A science fiction movie he saw as a teenager, “The Invisible Man,” furthered his interest in science. The plot featured a scientist who, using computers, developed a medicine to make matter invisible and then used it on human tissue.
The movie had a profound impact on him, Jung said, and motivated a growing interest in computational modeling and simulation.
“That was quite memorable. That was one motivation to do modeling,” he recalled.
What the future Eugene P. Wigner Fellow did not know then, however, was that he would end up studying physics, computational science, engineering and materials science — in Korea, Japan and the United States — all of which brought him to Oak Ridge National Laboratory and his Wigner Fellowship.
Jung, a member of the Computing and Computational Sciences Directorate at ORNL, is using his fellowship to develop essential tools of multiscale models for universal materials. He is interested in modeling materials using computational science to help develop new technology for new materials.
And there is almost nowhere better to do it, he said.
“There are a lot of resources for modeling and simulation, and people working on different experiments and topics. It’s really a nice opportunity to work with them,” Jung said.
“I want to synthesize and characterize the atomic level of material using computation. My goal is to study the fundamental, atomic scale using quantum mechanics to understand very small-scale properties, and try to upscale from that to a more meaningful scale used in manufacturing.”
The main contribution of his fellowship will be improving understanding of mechanical and thermodynamical behaviors of materials. “In the longer term, I hope my project will be the cornerstone of a virtual lab where novel materials can be designed, synthesized and characterized,” Jung said.
That virtual laboratory will enable scientists to analyze materials by combining and bridging advanced computational methods at different scales. Such understanding can help in the semiconductor industry, for example, perhaps leading to a better material for computer chips.
Energy efficiency is another area that could benefit from this research, and there are many others, Jung said, in which modeling for materials design and synthesis is important.
Working with ORNL’s C4WARD project, he is exploring how coal changes in the transition from the mine to more valuable products. These insights could inform how carbon fiber forms at the atomic scale and help identify what molecules would be good for carbon processing, he said.
Carbon capture is another area that could benefit from Jung’s research. “Maybe there is a new process or new material for a more energy-efficient way to capture carbon,” he said. “We need insight at the atomic scale to identify what molecule might be good for processing.
“I’m trying to develop a computational tool and models to help my colleagues who are working on that. I want to provide the understanding for them to work more efficiently,” he added.
Jung’s undergraduate experience in Japan helped develop his interests. Majoring in physics, he earned his master’s degree as well by creating his first simulation that could be applied to many different applications, such as biology, semiconductor manufacturing and designing structural materials at the atomic scale.
To satisfy South Korea’s military requirement, Jung worked at LG Corp. in semiconducting, electronics and optics, gaining experience with macroscale simulations. But, he said, he wanted to do more atomic-scale modeling. After learning parallel computing and creating a molecular dynamic simulation tool at a supercomputer institute in Korea, he joined MIT’s doctorate program in civil and environmental engineering. That allowed him to work at the atomic level with hydroxyapatite and collagen — the strong building blocks of human bone and muscle, as well as spider silk — studying the mechanisms that enable their strength.
At MIT, he worked on the application side of modeling, using molecular dynamics simulations to understand the atomic-scale behaviors of materials. “I had to develop my own tools and parameters for those applications,” he said.
His dissertation focused on developing multiscale models to understand fracture and synthesis processes of two-dimensional materials such as graphene, tungsten disulfide and molybdenum disulfide. Since joining ORNL as a Wigner Fellow, he has used the tools he developed as a doctoral student to examine how these materials behave at the atomic level when they grow, collaborating with other researchers at ORNL’s Center for Nanophase Materials Sciences to understand fundamental mechanisms and properties. The work was published in ACS Nano in 2021.
Mentored by Computational Chemistry and Nanomaterials Sciences group leader Stephan Irle, Jung develops integrated multiscale models that enable predictive design and simulation of materials.
Jung is happy to be in Oak Ridge. In Cambridge, Massachusetts, he, his wife and three young boys shared a two-room dormitory apartment for six years. Now they have a house with a yard and a lot more room to enjoy. He met his wife when she was a visiting student at his undergraduate college in Japan.
A singer with a musical group during his undergraduate days, Jung could have a K-Pop band with his boys, ages 10, 8 and 5, but he now leaves music to them. Instead, he fills free time with virtual study groups: a book club centered in Boston, and a long-time discussion group with Korean friends, with whom he explores machine learning and emerging tools for atomic-scale modeling. Jung and his family enjoy visiting the Dollywood amusement park near Knoxville, as well as hiking in the area, especially in the Great Smoky Mountains. — Lawrence Bernard
