T. Kawazoe et al., SPIN-RELAXATION PROCESS OF HOLES IN TYPE-II AL0.34GA0.66AS ALAS MULTIPLE-QUANTUM WELLS/, Physical review. B, Condensed matter, 47(16), 1993, pp. 10452-10455
We have measured the spin memory and the spin-relaxation times of hole
s in type-II quantum wells by means of pump-and-probe methods. The fas
t GAMMA-x interlayer scattering which is characteristic of type-II mul
tiple quantum wells allows us to observe directly the hole spin-relaxa
tion process. The hole spin relaxation is described by two decay compo
nents. The faster decay time ranges from 20 to 100 ps and depends on t
he number density of ''antiparallel-spin'' holes. This indicates that
the scattering between up-spin holes and down-spin holes is the major
spin-relaxation process of holes. The slower time component is about 2
0 ns, which is probably ascribed to the spin relaxation of localized h
oles in the well layers.