Negative initial phase shift of Kerr rotation generated from the building-up process of resident electron spin polarization in a CdTe single quantum well

Abstract

Initial phase shift in a precessional motion of resident electron-spin polarization is studied in a ${\mathrm{CdTe}/\mathrm{Cd}}_{0.85}{\mathrm{Mg}}_{0.15}\mathrm{Te}$ single quantum well using a time-resolved Kerr rotation technique. The generation dynamics of resident electron-spin polarization 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, the negative phase shift of the resident electron-spin polarization is observed, and the mechanism associated especially with a quick hole spin flip in negative trions is studied through the dependences on excitation power and magnetic field strength.