摘要

Graphene, a single layer of carbon atoms, exhibits novel two-dimensional electronic behavior characterized by massless Dirac electrons. In particular, its physical properties can be strongly modified by electrical gating and layer-layer interactions. Optical spectroscopy provides a powerful tool for probing the unusual phenomena in graphene. In this talk, I will describe gate dependent optical transitions monolayer graphene and a continuously tunable bandgap in bilayer graphene. I will further show that the gapped bilayer graphene corresponds to a massive Dirac electron system that features topologically protected boundary states.

报告人简介

Feng Wang received his physics Ph.D. from Columbia University in 2004. In 2005, he went to Univeristy of California, Berkeley as a Miller research fellow. Later he joined the physics department in UC Berkeley as an assistant professor in 2007. He was awarded the Sloan fellowship in 2008, the IUPAP C10 young scientist prize in 2009, the PECASE award and the Packard fellowship for science and engineering in 2010.

Feng Wang has made seminal contributions to understanding optical and optoelectronic properties of carbon nanomaterials and atomically thin layered materials. He demonstrated experimentally the excitonic nature of optical transitions in carbon nanotubes, and discovered the unique field-tunable optical properties in graphene. He also realized a widely tunable semiconducting bandgap in bilayer graphene through electrical gating, discovered the indirect-to-direct bandgap transition in monolayer MoS2, and studied ultrafast dynamics in these layered materials.