X. Marie et al., Electron-spin quantum-beat dephasing in quantum wells as a probe of the hole band structure, PHYS REV B, 61(16), 2000, pp. 11065-11077
Time-resolved optical pumping experiments under transverse magnetic field a
t oblique incidence with respect to the growth axis have been performed on
various quantum-well (QW) structures. When the incident photon energy is no
nresonant with the heavy-hole exciton, the electron-spin quantum beats, whi
ch manifest the electron-spin Larmor precession, dephase with respect to th
e normal-incidence case. We show that the direction of the electron-spin pr
ecession can be deduced, which provides a method to determine unambiguously
the sign of the conduction-electron g factor. Moreover, the amplitude of t
he dephasing is very sensitive to the mixing of the heavy- and light-hole s
tates in the valence bands that are involved in optical transitions at a gi
ven photon energy. A theory of optical pumping of QWs under arbitrary incid
ence, based on the valence-band description in the effective-mass approxima
tion, has been developed. It accounts quite well for the experimental obser
vations.