OSC Colloquium: Xiaoqin Elaine Li, "The Versatile World of Excited States in Semiconductor Moiré Superlattices"

Title

The Versatile World of Excited States in Semiconductor Moiré Superlattices 

Abstract

In van der Waals bilayers, the strict requirement of lattice matching at the interface is lifted. The periodic changes in atomic alignment lead to the formation of an in-plane superlattice, known as the moiré superlattice. The twist angle acts as a unique knob to control the material properties. I will discuss how different types of excited states, i.e. excitons and trions can be engineered in semiconductor moiré superlattices.  I will discuss two recent developments. One is the discovery of a charge-transfer trion resonance in twisted homobilayers. Another is to confine excitons in a semiconductor functional layer with twisted-hBN substrates.  

Bio

Prof. Li is a professor in the physics department at the University of Texas-Austin. She received her Ph.D. at the University of Michigan in 2003 and worked as a postdoctoral researcher at JILA, Colorado. Since establishing her research group at the University of Texas in 2007, she has worked in several research areas including low-dimensional semiconductors, most recently in atomically thin van der Waals materials, magnetic materials, and nanophotonics. She has received several awards including the Presidential Early Career Award for Scientists and Engineers in the U. S. and a Sloan Fellowship. She was a Humboldt research fellow at the Technical University of Berlin between 2013-2015. She is a fellow of the American Physics Society and OPTICA.  

Contact

Florian Willomitzer, Colloquium Chair & Professor: colloquium@optics.arizona.edu