Anomalous non-equilibrium response in black phosphorus to sub-gap mid-infrared excitation.

ABSTRACT: The competition between the electron-hole Coulomb attraction and the 3D dielectric screening dictates the optical properties of layered semiconductors. In low-dimensional materials, the equilibrium dielectric environment can be significantly altered by the ultrafast excitation of photo-carriers, leading to renormalized band gap and exciton binding energies. Recently, black phosphorus emerged as a 2D material with strongly layer-dependent electronic properties. Here, we resolve the response of bulk black phosphorus to mid-infrared pulses tuned across the band gap. We find that, while above-gap excitation leads to a broadband light-induced transparency, sub-gap pulses drive an anomalous response, peaked at the single-layer exciton resonance. With the support of DFT calculations, we tentative

SUBMITTER: Montanaro A 

PROVIDER: S-EPMC9106664 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature