Individual contribution of electrons and holes to photocarrier-induced bandgap renormalization in intrinsic bulk GaAs

摘要

With the advent of semiconductor spintronics, spin-polarized electron-hole plasmas could occur in semiconductors, leading to spin-dependent many-body effects. To understand these many-body effects, spin-dependent bandgap renormalization (BGR) often needs to be calculated quantitatively, which requires to know the fractional contribution of electrons (k) to the total BGR induced by the electron-hole plasma. However, the measurement of the k value is challenging because BGR is usually submerged or partially offset by the strong band-filling effect. Facing this challenge, we develop a new experimental technique which could measure spin-dependent many-body effects without the influence from the band-filling effect. The presented technique is employed in intrinsic bulk GaAs, with a dynamic model developed to extract the k value from the measured data. It is found that the k value in bulk GaAs increases with increasing concentration of the photoinjected electron-hole plasma but is consistently much less than the reported value in GaAs quantum wells. These results reveal obviously different many-body interactions in bulk GaAs and its quantum wells.