title: Direct observation of the electron spin relaxation induced by nuclei in quantum dots.
abstract: We have studied the electron spin relaxation in semiconductor InAs/GaAs quantum dots by time-resolved optical spectroscopy. The average spin polarization of the electrons in an ensemble of p-doped quantum dots decays down to 1/3 of its initial value with a characteristic time T(Delta) approximately 500 ps, which is attributed to the hyperfine interaction with randomly oriented nuclear spins. We show that this efficient electron spin relaxation mechanism can be suppressed by an external magnetic field as small as 100 mT.
authors.affiliation: LNMO, INSA 135 Avenue de Rangueil, 31077 Toulouse CEDEX 4, France.
authors.forename: P-F
authors.initials: PF
authors.lastname: Braun
authors.forename: X
authors.initials: X
authors.lastname: Marie
authors.forename: L
authors.initials: L
authors.lastname: Lombez
authors.forename: B
authors.initials: B
authors.lastname: Urbaszek
authors.forename: T
authors.initials: T
authors.lastname: Amand
authors.forename: P
authors.initials: P
authors.lastname: Renucci
authors.forename: V K
authors.initials: VK
authors.lastname: Kalevich
authors.forename: K V
authors.initials: KV
authors.lastname: Kavokin
authors.forename: O
authors.initials: O
authors.lastname: Krebs
authors.forename: P
authors.initials: P
authors.lastname: Voisin
authors.forename: Y
authors.initials: Y
authors.lastname: Masumoto