Attosecond Carrier Dynamics in Layered and Quasi-2D Semiconductors*

2D and quasi-2D materials have unique electronic properties due to quantum confinement effects, broken symmetries and the layered crystal structure. Some of these aspects have been investigated in some detail in the steady-state regime, but their impact on quasiparticle and carrier dynamics is at present unclear. Relevant time-scales extend from picoseconds to the inherent electronic time-scales in the attosecond regime.

In this talk I will demonstrate how the full 3D crystal of a layered material behaves as a 2D material on fs and sub-fs time-scales. I will then show how the electronic structure of MoS₂ as a paradigmatic 2D material can be drastically renormalized, pushing carrier dynamics into the regime of 100 attoseconds. Reasons for this dramatic change will be explored, and implications for  the design of optoelectronic and spintronic devices based on layered materials will be discussed.