In a strongly correlated electronic system, Coulomb interactions among electrons dominate over kinetic energy. Recently, two-dimensional (2D) moiré superlattices of van der Waals materials have emerged as a promising platform to study correlated physics and exotic quantum phases in 2D. In transition metal dichalcogenides (TMDCs) based moiré superlattices, the combination of large effective mass and strong moiré coupling renders the easier formation of flat bands and stronger electronic correlation, compared with graphene moiré superlattices. Meanwhile, the strong Coulomb interaction in 2D also leads to tightly bound excitons with large binding energy in TMDCs. In this talk, we will discuss how to use optical spectroscopy to investigate excitonic physics and strongly correlated phenomena in TMDC moiré superlattice, along with correlated exciton states arising from strong interactions.
 

Sufei Shi is currently an Associate Professor in the Physics Department at Carnegie Mellon University. He obtained a B.S. in Physics from Nanjing University and an M.S. in Physics from Brown University. He obtained his Ph. D in Physics from Cornell University in 2012, and he did his postdoc work at UC Berkeley from 2011 to 2015. He joined Rensselaer Polytechnic Insitute as an Assistant Professor in 2015 and was then promoted to Associate Professor in 2021. He was awarded the ACS Petroleum Research Fund Doctoral New Investigator award in 2018 and the NSF Career award in 2020.

Please contact phweb@ust.hk should you have questions about the talk.