Physics Colloquium | Electrons in 2-Dimensional Semiconductor Atomic Layers, Sept. 4

Kin Fai Mak

The Physics & Astronomy Colloquium Series presents Kin Fai Mak of the Pennsylvania State University on “Electrons in 2-dimensional semiconductor atomic layers” on Friday, Sept. 4, at 4:10 p.m. in Walter 245.

Abstract:  The unique electronic properties of graphene have attracted tremendous interests. While the discovery of the material is highly important in its own right, it has stimulated the advances in other novel 2-dimensional materials and phenomena. In this talk, I will discuss the interesting physics of a class of 2-dimensional semiconductor atomic layers: group-VI transition metal dichalcogenides (e.g. MoS2, MoSe2, WS2, WSe2 …). Their electrons can be viewed as massive Dirac fermions that arise from an emergent coupling between the electronic pseudospin and orbital degrees of freedom. Such a 2-dimensional electronic system gives rise to many unique optical and electrical properties. In this talk, I will discuss our recent experimental studies on the strong excitonic interactions in these materials, the optical generation of long-lived pseudospin/valley polarizations and the observation of a new valley Hall effect.