Investigation of spin dynamics based on initial phase shift analysis of Kerr rotation in a CdTe single quantum well

We have studied the spin dynamics of the resident electron spin polarization (RESP) based on the initial phase shift of the Larmor precessions in a CdTe single quantum well by using a time-resolved Kerr rotation technique. The generation dynamics of RESP involve the formation and transformation of the associated optically excited states and are complicated particularly in the early time region. A careful analysis of the phase shift gives a deep understanding of the generation processes. In the experiments in the excitation energy range between the negative trion and neutral exciton resonances, the anomalous negative phase shift was observed, and the mechanism associated especially with a quick hole spin-flip and transformation to trions from excitons are discussed through the dependences on excitation energy, excitation power, and magnetic field strength.