Tuning of the hole spin relaxation time in single self-assembled In${}_{1-x}$Ga${}_x$As/GaAs quantum dots by electric field

We investigate the electric field tuning of the phonon-assisted hole spin relaxation in single self-assembled In${}_{1-x}$Ga${}_x$As/GaAs quantum dots, using an atomistic empirical pseudopotential method. We find that the electric field along the growth direction can tune the hole spin relaxation time for more than one order of magnitude. The electric field can prolong or shorten the hole spin lifetime and the tuning shows an asymmetry in terms of the field direction. The asymmetry is more pronounced for the taller the dot. The results show that the electric field is an effective way to tune the hole spin-relaxation in self-assembled QDs.