Spin dynamics of electron with high excess energy in GaAs investigated by the simplified circularly dichromatic pump-probe model

Time-resolved circularly polarized pump-probe spectroscopy is used to study the spin dynamics of electron with high excess energy in bulk GaAs at room temperature, an abnormal phenomenon that the curve taken from co-helicity circularly polarized pump-probe beam drops below the curve taken from cross-helicity circularly polarized pump-probe beam is observed. With both the spin-dependent band-filling and band-gap renormalization effects being taken into account, a simplified circularly dichromatic pump-probe model is further developed, the model can be used to fit the scanning experimental traces to retrieve the spin relaxation time, carrier recombination time, intensity coefficient of spin-dependent band-filling and band-gap renormalization effects. etc. With the parameters retrieved from the experimental data, the physical origin of the spectrum reversal can be explained in detail, both of the spin-dependent band-filling and band-gap renormalization effects contribute to the reversal spectrum. (C) 2013 Elsevier B.V. All rights reserved.