title: Anomalous Hanle effect due to optically created transverse overhauser field in single InAs/GaAs quantum dots.
abstract: We report on experimental observations of an anomalous Hanle effect in individual self-assembled InAs/GaAs quantum dots. A sizable electron spin polarization photocreated under constant illumination is maintained in transverse magnetic fields as high as approximately 1 T, up to a critical field where it abruptly collapses. These striking anomalies of the Hanle curve point to a novel mechanism of dynamic nuclear spin polarization giving rise to an effective magnetic field generated perpendicular to the optically injected electron spin polarization. This transverse Overhauser field, confirmed by the cancellation of electron Zeeman splitting below the critical field, is likely to be a consequence of the strong inhomogeneous quadrupolar interactions typical for strained quantum dots.
authors.affiliation: CNRS-Laboratoire de Photonique et de Nanostructures, Route de Nozay, 91460 Marcoussis, France.
authors.forename: O
authors.initials: O
authors.lastname: Krebs
authors.forename: P
authors.initials: P
authors.lastname: Maletinsky
authors.forename: T
authors.initials: T
authors.lastname: Amand
authors.forename: B
authors.initials: B
authors.lastname: Urbaszek
authors.forename: A
authors.initials: A
authors.lastname: Lemaître
authors.forename: P
authors.initials: P
authors.lastname: Voisin
authors.forename: X
authors.initials: X
authors.lastname: Marie
authors.forename: A
authors.initials: A
authors.lastname: Imamoglu