2021/11/24 by Angela Montanaro, Montanaro, Angela, Francesca Giusti +23
Materials Science · Engineering · #2D Materials and Applications #Perovskite Materials and Applications #Ga2O3 and related materials
paper · pdf · doi:10.48550/arxiv.2111.12355
The competition between the electron-hole Coulomb attraction and the\nthree-dimensional dielectric screening dictates the optical properties of\nlayered semiconductors. In low-dimensional materials, the equilibrium\ndielectric environment can be significantly altered by the ultrafast excitation\nof photo-carriers, leading to renormalized band gap and exciton binding\nenergies. Recently, black phosphorus emerged as a 2D material with strongly\nlayer-dependent electronic properties. Here, we resolve the coherent response\nof screening to sub-gap photo-excitation in bulk black phosphorus and find that\nmid-infrared pulses tuned across the band gap drive a transient non-thermal\nsuppression of the dielectric screening, which is revealed by the emergence of\nthe single-layer exciton resonance. Our work exposes the role of interlayer\ninteractions in determining the electronic properties of 2D materials and\ndiscloses the possibility of optically manipulate them, which is of great\nrelevance for the engineering of versatile van der Waals low-dimensional\nmaterials.\n