Spin relaxation in sub-monolayer and monolayer InAs structures grown in GaAs matrix
Abstract
Electron spin dynamics in InAs/GaAs heterostructures consisting of a single layer of InAs (1/31 monolayer) embeded in (001) and (311)A GaAs matrix was studied by means of time-resolved Kerr rotation spectroscopy. The spin relaxation time of the sub-monolayer InAs samples is significantly enhanced, compared with that of the monolayer InAs sample. We attributed the slowing of the spin relaxation to dimensionally constrained Dyakonov-Perel mechanism in the motional narrowing regime. The electron spin relaxation time and the effective g-factor in sub-monolayer samples were found to be strongly dependent on the photon-generated carrier density. The contribution from both Dyakonov-Perel mechanism and Bir-Aronov-Pikus mechanism were discussed to interpret the temperature dependence of spin decoherence at various carrier densities.