Ultrafast energizing the parity-forbidden dark exciton in black phosphorus.

ABSTRACT: As conventional electronic materials approach their physical limits, the application of ultrafast optical fields to access transient states of matter captures imagination. The inversion symmetry governs the optical parity selection rule, differentiating between accessible and inaccessible states of matter. To circumvent parity-forbidden transitions, the common practice is to break the inversion symmetry by material design or external fields. Here we report how the application of femtosecond ultraviolet pulses can energize a parity-forbidden dark exciton state in black phosphorus while maintaining its intrinsic material symmetry. Unlike its conventional bandgap absorption in visible-to-infrared, femtosecond ultraviolet excitation turns on efficient Coulomb scattering, promoting carrier mult

SUBMITTER: Shen G 

PROVIDER: S-EPMC12037752 | biostudies-literature | 2025 Apr

REPOSITORIES: biostudies-literature