Slow Exciton Spin Relaxation in Single Self-Assembled In${}_{1-x}$Ga${}_x$As/GaAs Quantum Dots

Abstract

We calculate the acoustic phonon-assisted exciton spin relaxation in single self-assembled In${}_{1-x}$Ga${}_x$As/GaAs quantum dots using an atomic empirical pseudopotential method. We show that the transition from bright to dark exciton states is induced by Coulomb correlation effects. The exciton spin relaxation time obtained from sophisticated configuration interaction calculations is approximately 15--55 $\mu$s in pure InAs/GaAs QDs and even longer in alloy dots. These results contradict previous theoretical and experimental results, which suggest very short exciton spin times (a few ns), but agree with more recent experiments that suggest that excitons have long spin relaxation times ($>$ 1 $\mu$s).

References in corpus (8)

• Theory of electron spin decoherence by interacting nuclear spins in a quantum dot
• Spin decoherence of a heavy hole coupled to nuclear spins in a quantum dot
• Spin relaxation and decoherence of holes in quantum dots
• Observation of extremely slow hole spin relaxation in self-assembled quantum dots
• Nuclear Spins in Nanostructures
• Exciton polarization, fine structure splitting and quantum dot asymmetry under uniaxial stress
• Dephasing of electron spin qubits due to their interaction with nuclei in quantum dots
• Atomistic theory of spin relaxation in self-assembled In${}_{1-x}$Ga${}_x$As/GaAs quantum dots at zero magnetic field

Cited by in corpus (2)

• Hole spin-flip transitions in a self-assembled quantum dot
• Entanglement Dynamics of Molecular Exciton States in Coupled Quantum Dots