Engineering of domains and domain boundaries is quintessential for technological exploitation of numerous functional materials. However, it has only recently realized that the configurations of these domains/domain walls with 2D-vector vorticity can have non-trivial topology, and these topological vortex domains are rather universal, unless long-range interaction such as ferroelastic coupling or dipolar coupling dominates. We have also found vortex-like domain configurations, which have vorticity in energy diagram, but not in real space, and are called pseudo-vortex domains. We will discuss the difference between these two types of domain configurations in a number of quantum materials, especially with coexisting multiple orders of charge/spin/lattice degrees of freedom.

Bio：Cheong has made ground-breaking contributions to the research field of enhanced physical functionalities in complex materials originating from collective correlations and collective phase transitions such as colossal magnetoresistive and colossal magnetoelectric effects in complex oxides. He has also made pivotal contributions to mesoscopic self-organization in solids, including the nanoscale charge stripe formation, mesoscopic electronic phase separation in mixed valent transition metal oxides, and the formation of topological vortex domains in multiferroics, which was found to be synergistically relevant to mathematics (graph theory) and even cosmology. He has published more than 780 scientific papers, and the total citation is more than 47,000 (Web of Science: six papers cited more than 1000 times, and his h-index is 104). His educational background includes mathematics in college, string theory (about three years) in graduate school, and solid state physics for Ph. D.. He has worked at Los Alamos National Laboratory, AT&T Bell Laboratories, and Rutgers Center for Emergent Materials (RCEM), Rutgers University. He is currently the director of center for Quantum Materials Synthesis, the director of Rutgers Center for Emergent Materials, a Henry Rutgers Professor and a Board of Governors Professor at Rutgers, a Distinguished Visiting Professor at Postech in S. Korea as well as in Nanjing University in China. His work on complex oxides has been recognized through various prizes, including the 2007 Hoam Prize sponsored by Samsung, the KBS 2009 Global Korean Award, and the 2010 James C. McGroddy Prize for New Materials sponsored by IBM.