Suk Hyun Sung (Harvard): Materials Science and Engineering Seminar

Title: “Atomic-Scale Engineering of Quantum Materials via Advanced In-Situ Electron Microscopy”

Suk Hyun Sung

Postdoctoral Fellow, Harvard University Rowland Institute

Dr. Suk Hyun Sung is a postdoctoral fellow at the Rowland Institute at Harvard, working with Principal Investigator Dr. Ismail El Baggari. He received his Ph.D. in Materials Science and Engineering from University of Michigan under supervision of Prof. Robert Hovden in 2023. He earned his B.S. in Engineering Physics from Cornell University in 2016. His research focuses on understanding and manipulating quantum materials at the atomic scale.

Research Synopsis:

Quantum materials offer tremendous prospects in next-generation devices for computing, sensing and detection. A key feature of quantum materials is extreme sensitivity to small perturbations, which provides powerful tuning knobs such as chemical composition, electric and magnetic fields, light, pressure, and strain. Even picometer-scale shifts in the atomic lattice can trigger dramatic electronic changes such as metal-insulator transitions. That said, this extreme sensitivity also makes quantum materials susceptible to nano- and meso-scale fluctuations, which can obscure measurements of their bulk properties. Therefore, we need new synthesis techniques that protect and realize these fragile exotic states, and characterization methods that probe the picoscale order parameter over nano- or meso-scale where it becomes relevant for device fabrications.

In this talk, I will discuss how scanning transmission electron microscopy (STEM) enables the development of new atomic-scale synthesis methods and direct observation of quantum materials at the atomic level. First, I will showcase how we can access non-equilibrium, metastable crystal structures in 2D materials with novel polytype layer sequences. This method, coined endotaxial engineering, has been shown to realize new quantum phases and enhance long-range order. Second, I will highlight how we can realize new crystal periodicities through twisting and intercalation. Towards the end of the talk, I will discuss state-of-the-art cryogenic electron microscopy with liquid helium and other in situ capabilities to directly probe emergent phases in quantum, magnetic, and electronic materials.