时间： 12月21日（周四）15:00

地点： 物理馆323

报告题目：Explore Complex Materials with IR and THz near-field Microscopy and Spectroscopy

报告人：Prof. Mengkun Liu, Stony Brook University

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 near-field IR and THz spectroscopy and discuss their applications in the nanoscale electrodynamics in SECM. Specifically, I will discuss the details of modeling scanning near-field infrared microscopy and its application in understanding the mesoscopic insulator to metal phase transitions in VO2 and Ca2RuO4 with 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 at the nanoscale.

Mengkun Liu (Ph.D. 2012 Boston University) is an assistant professor at the Physics Department of Stony Brook University (since Jan. 2015). His post doc research is at UC San Diego from 2012-2014. His research interests include physics of correlated electron systems, two-dimensional materials, infrared and terahertz nano-optics and ultrafast time-domain spectroscopy.  Prizes include Seaborg Institute Research Fellowships at Los Alamos National Lab (2009, 2010).