Hole spin relaxation in InAS/GaAs quantum dot molecules

Abstract

We calculate the spin–orbit induced hole spin relaxation between Zeeman sublevels of vertically stacked InAs quantum dots. The widely used Luttinger–Kohn Hamiltonian, which considers coupling of heavy- and light-holes, reveals that hole spin lifetimes (T 1) of molecular states significantly exceed those of single quantum dot states. However, this effect can be overcome when cubic Dresselhaus spin–orbit interaction is strong. Misalignment of the dots along the stacking direction is also found to be an important source of spin relaxation.