[Jan. 25] Physics Special Seminar - Dr. Min Gu Kang (Cornell Univ.)

물리학과 특별세미나 개최 안내

물리학과에서는 특별세미나를 아래와 같이 개최하오니 관심있는 분들의 많은 참석을 바랍니다.

1. 연사: 강민구 박사 (Cornell Univ.)
2. 일시: 2024. 1. 25(목), 오후 2시
3. 장소: 공학3동 302호 (세미나실)

4. 제목: New flat band materials platform based on line-graph lattice geometry

Flat band materials based on Moiré technology have achieved tremendous success over the past few years, realizing a rich array of exotic phases of matter at the intersection of strong electronic interaction and nontrivial quantum geometry. However, the temperature scale of Moiré flat band physics has been fundamentally limited to low temperatures due to the large Moiré length scale and low flat band electron density.

In this talk, I will discuss a new design principle of flat band materials based on line-graph lattice geometries. Taking the kagome lattice and the pyrochlore lattice as representative examples of 2D and 3D line-graph lattices, respectively, I will demonstrate the experimental realization of line-graph flat bands in kagome metal CoSn and pyrochlore metal CaNi₂. Once these kagome and pyrochlore flat bands are tuned to the Fermi level by chemical substitution, we observed the emergence of flat band magnetism and superconductivity, respectively. A comparison of the temperature scales of these emergent phenomena in Moiré and line-graph flat bands reveals that the line-graph flat band systems offer promising opportunities to realize flat band physics at significantly higher temperature scales. I note that the kagome and pyrochlore lattices are merely examples within the much wider line-graph, split-graph, and bipartite lattice families – this emphasizes that there are a plethora of other geometric motifs to be explored and potential flat band materials to be discovered in the future in this new area of research.