Two-phonon process and hyperfine interaction limiting slow hole-spin relaxation time in InAs/GaAs quantum dots

Francois Fras (1) , Benoit Eble (1) , Pascal Desfonds (1) , Frédéric Bernardot (1) , Christophe Testelin (1) , Maria Chamarro (1) , Audrey Miard (2) , Aristide Lemaître (2)

1 INSP - Institut des Nanosciences de Paris
2 LPN - Laboratoire de photonique et de nanostructures

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.

Mots clés: Spin relaxation and scattering; Optical creation of spin polarized carriers; III-V semiconductors; Quantum dots; hyperfine interaction; phonon

Domaines: Physique Quantique [quant-ph]

Francois Fras, Benoit Eble, Pascal Desfonds, Frédéric Bernardot, Christophe Testelin, et al.. Two-phonon process and hyperfine interaction limiting slow hole-spin relaxation time in InAs/GaAs quantum dots. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2012, 86, pp.45306. ⟨10.1103/PHYSREVB.86.045306⟩. ⟨hal-00913528⟩