Two-phonon process and hyperfine interaction limiting slow hole-spin relaxation time in InAs/GaAs quantum dots
Résumé
We study the hole-spin relaxation in p-doped InAs quantum dots. Two relaxation mechanisms are evidenced, at low magnetic field (0≤B≤2T) and low temperature (2≤T≤50K), by using a pump-probe configuration and a recent experimental technique working in the frequency domain. At T=2K, the coupling to nuclear spins and the hole wave-function inhomogeneity fix the hole-spin relaxation rate value, Γ1h≈1μs-1. It decreases with increasing magnetic field and reaches a plateau at 0.4 μs-1. At T≥7K, two-phonon spin-orbit process dominates and leads to a quadratic temperature dependence of Γ1h, in good agreement with theory.
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