Bandgap renormalization governs the ultrafast response of single-layer MoS 2

Two-dimensional crystals of transition metal dichalcogenides (TMDs) are attracting growing interest due to their unique electronic and optical properties, resulting in the demonstration of functional devices. On the more fundamental side, they represent ideal systems for exploring the physics of 2D semiconductors, where the electron-electron interaction is strongly enhanced by both quantum confinement and the reduced screening.