报告题目：Explore Strongly Correlated Electron Materials with IR near-field Microscopy and Spectroscopy

报 告 人：Mengkun Liu，Stony Brook University

报告时间：2017年8月28日10:00

报告地点：理科楼C302报告厅

报告摘要：In strongly correlated electron materials (SCEM), the delicate interplay between spin, charge, and lattice degrees of freedom often leads to extremely rich phase diagrams exhibiting intrinsic phase inhomogeneities. The key to studying and disentangling such complexities in SCEM usually lies in the characterization and control of the materials at fundamental energy, time and length scales. I will use this opportunity to report the recent advances in the IR and THz spectroscopy and explain how they can be used to probe electronic/structural phase transitions with unprecedented spatial and temporal resolutions. Specifically, with scanning near-field infrared microscopy we resolved the insulator to metal phase transitions in SCEM such as VO2, Ca2RuO4 with ~10 nm resolution over a broad spectral range (350 cm-1 to 2500 cm-1). I will also discuss the future development of near-field scanning microscope including the cryogenic capabilities and its coupling to ultrafast pump probe spectroscopy. These results set the stage for future spectroscopic investigations to access the fundamental properties of complex materials.