Observation of a many-body edge singularity in quantum well luminescence spectra.

The observation of a many-body, Fermi-energy edge singularity in the low-temperature photoluminescence spectra of InGaAs-InP quantum wells is reported. Strong enhancement of the photoluminescence intensity towards the electron Fermi energy (${E}_{\mathrm{F}}^{e}$) is observed, due to multiple electron-hole scattering processes to states above ${E}_{\mathrm{F}}^{e}$. Recombination of electrons in states up to ${E}_{\mathrm{F}}^{e}$ is allowed by hole localization. The many-body processes are analogous to the core-hole phenomena in the soft-x-ray emission spectra of metals.