Quantum Matter Seminar: Exploring novel electronic states in epitaxial 2D metal halides with STM
高春雷
复旦大学物理学系
报告时间：2024年5月13日（周一）下午15:30
报告地点：紫金港校区段永平教学楼2号楼212报告厅
摘要：
Two-dimensional metal halides recently invoked tremendous interest due to the discovery of ferromagnetism in the monolayer limit. In fact, metal halides represent a rich family of materials which can host various novel properties such as 2D ferromagnetism, Mott insulator, quantum spin liquid and so on. In this talk, I will briefly review our effort in growing metal halides by molecular beam epitaxy and in investigating their structure, electronic, and magnetic properties with scanning tunneling microscopy(STM). In particular, I will discuss two recent discoveries in detail. The first is the Rydberg-like interface states in the YbCl3/highly oriented pyrolytic graphite heterostructure. Combining STM and first-principle calculations, a comprehensive understanding of the electronic structure of rare-earth insulator YbCl3 is established, and in-gap states with Rydberg-like orbitals are directly visualized. The second is the dipolar soliton in the CoCl2 monolayer. We show that the solitons are essentially intrinsic dipoles driven by cooperative charge-lattice distortion around individual CoCl6 octahedrons, which strongly breaks the translational symmetry by the unexpected extreme self-localization. Our findings demonstrate the rich novel physics in metal halides and the unique advantages of STM in exploring them.
报告人简介：
Chunlei Gao, Professor of Physics at Fudan University. Dr. Gao received his bachelor’s and Master’s degrees from Fudan University. In 2006, he obtained his Ph.D. from the Max-Planck-Institute of Microstructure Physics in Germany where he spent two more years for a post-doc. He joined Shanghai Jiaotong University in 2009 and moved to Fudan University in 2015. His research focuses on the investigation of surface magnetic and electronic structures with scanning tunneling microscopy. Currently, the research activity in his group is mainly on quantum magnetism and correlated phenomena in two-dimensional systems.
