Magnetic field control of the optically generated spin kinetics: effect of the exchange field

Abstract

Spin transport kinetics and control in semiconductor quantum wells (QWs) have been investigated under magnetic field applied externally. Spins generated optically by a circularly polarized light are controlled by varying the strength and orientation of the magnetic field. The kinetics of spins is explored in terms of the spin oscillation, precession frequency, polarization amplitude and decay rate, and the electron g-factor. The determined components of the electron g-factor in QW are agreed well with those in the literature. The results, however, show that the velocity (speed and direction) of the electron spin precession can be determined by the total field, which is a vector sum of the magnetic field and the exchange field acting in parallel to the growth axis of the QW hererostructure.