Research Presentation: Hanjong Paik

DateDecember 14, 2021
Time2:00 - 3:00 pm
LocationBaylor Sciences Building, Room E234
Dr. Hanjong Paik

Platform for the Accelerated Realization, Analysis, and

Discovery of Interface Materials (PARADIM),

Department of Materials Science and Engineering, Cornell University

Exploring Functional Oxides: MBE Approach for New Quantum Materials Discovery

The synthesis of complex oxide thin films by molecular-beam epitaxy (MBE) technique (utilizing precise control of low-energy atomic beam-flux) provides a great potential for unleashing novel and hidden properties of the material from the dull ground states. I believe, one of the most important factors in new interface materials discovery is the epitaxial stabilization, which is imposed from the underlying iso- (or hetero-) structural substrates. By considering substrates with a proper crystal symmetry, orientation, and (maximum and/or minimum) strain value, the properties of oxide thin films can be
dramatically altered in comparison to their bulk form. Occasionally, this approach results in metastable and pseudomorphic polymorphism and thus introducing dramatically unexpected emergent properties owing to the power of epitaxial-strain-symmetry-stabilization at the interface. Therefore, MBE thin-film approach for new quantum material discovery will be the ultimate platform for the fundamental study of new quantum phenomena at the surface and interface, in contrast, it is not possible to investigate in the form of traditional bulk- and nano-powder samples.

In this talk, I would like to present how ozone-assist oxide MBE can be useful to discover new
material properties, especially, relevant to the strongly correlated electronic system. I will talk about (1) room temperature high-electron-mobility and its 2DEG behavior of the perovskite stannate interface for the transparent power electronics (2) metal-insulator transition (MIT) behavior of ultrathin VO2 films for the hybrid device applications (3) how simple metal ruthenium dioxide becoming a superconductor via. strain-stabilization, and (4) realization of epitaxial topological crystalline insulator Sr3SnO
anti-perovskite system with in-situ spectroscopy. In addition to describing the above material
synthesis and characterization, I also would like to discuss several challenging materials systems, for example, some of cubic-to-hexagonal perovskite polymorphic system, noble pyrochlore oxides
system, and materials growth challenges containing alkaline metal elements (i.e., Li-, K-, Nacontaining material system) for the fundamental study of quantum materials.

For more information, please contact Dr. Zhenrong Zhang: 254-710-2419 /
PublisherDepartment of Physics
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