Effect of the anisotropy of the electron g-factor in spin polarization

Spin polarization in the presence of an external magnetic field and electric bias in quantum confined semiconductor structures has been studied by time- and polarization-resolved spectrometry. From measurements with angular variations of the magnetic field from the Voigt configuration (VC) it was found that both the frequency (Omega) and decay rate (beta) of the oscillatory component of the polarization increase with variation of the angle from the VC. Their dependences are discussed based on the electron spin dephasing related to the spread of the electron g-factor (g(e)) (i.e. unequal values of the longitudinal (g(e parallel to)) and transverse (g(e perpendicular to)) components of g(e)) and the exchange interaction between the electron and hole spins. It is demonstrated that the increase in Omega upon deviation of the magnetic field from the VC relates to the anisotropy of g(e) (g(e parallel to) and g(e perpendicular to)) resulting from the quantum confinement effect. However, the angular dependence on beta is related to the residual exchange interaction between the electron spin and rapidly relaxing hole spin. (C) 2009 Elsevier B.V. All rights reserved.