BREAKDOWN OF THE ONE-ELECTRON PICTURE IN OPTICAL SPECTROSCOPY OF LOW-DIMENSIONAL ELECTRON-SYSTEMS - 3 ANOMALIES AROUND THE FERMI-LEVEL

We report three distinct anomalies in emission, absorption and linear emission polarization of two-dimensional degenerate electron systems w ith tunable lateral potential modulation. We show that they occur for convergent as well as singular Fermi edges with a unique threshold ene rgy below the Fermi level. The resulting spectral hole for convergent edges significantly breaks down the determination of the Fermi energy in the one-electron picture from photoluminescence spectra. (C) 1998 A cademic Press.