INTERBAND QUANTUM KINETICS WITH STATIC DISORDER SCATTERING .2. COMPETITION OF LIGHT AND DISORDER FOR ADIABATIC PULSES

Simultaneous action of strong light pulses and of a strong scattering on the compositional disorder in semiconductor alloys can be treated i n the CPA analytically and numerically up to explicit results for mono chromatic pulses, which are adiabatic, i.e., changing slowly on the ti me scale of the quasiparticle formation time. We show that it is possi ble to construct the adiabatic electron self-energy as a sequence of s elf-energies for constant illumination parametrically dependent on the transient illumination strength. These are obtained by mapping the pr oblem on a well known alloy case with an effective band hybridisation. Main effects concentrate to a narrow energy region around the one-pho ton resonance. We study in detail the behavior of the self-energy in t his region in dependence on the basic model parameters. An important q uestion is the occurence of the optically induced gap. Both the numeri cal analysis and an analytical treatment demonstrate a delayed formati on of the gap in comparison with the pure crystal case, with a gradual distortion of the electronic structure around the resonance. The gap width scales according to the 2/3 power law.