D. Dunker

Exciton recombination dynamics in an ensemble of (In,Al)As/AlAs quantum dots with indirect band-gap and type-I band alignment

T. S. Shamirzaev, J. Debus, D. S. Abramkin, D. Dunker, D. R. Yakovlev, D. V. Dmitriev, A. K. Gutakovskii, L. S. Braginsky, K. S. Zhuravlev, and M. Bayer A. V. Rzhanov Institute of Semiconductor Physics, Siberian branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany and A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia

Spin relaxation of negatively charged excitons in (In,Al)As/AlAs quantum dots with indirect band gap and type-I band alignment

Spin dynamics of negatively charged excitons is experimentally studied in (In,Al)As/AlAs quantum dots with indirect band gap and type-I band alignment. At low temperatures of 1.8 K, the spin relaxation time is 55 μs in a magnetic field of 3 T. It decreases with increasing magnetic field as B−5, which evidences that the spin relaxation of the negatively charged excitons is provided by an one-acoustic-phonon process.

Spin-flip Raman scattering of the neutral and charged excitons confined in a CdTe/(Cd,Mg)Te quantum well

Spin-flip Raman scattering of electrons and heavy-holes is studied for resonant excitation of neutral and charged excitons in a CdTe/Cd

Spin-flip Raman scattering of the Γ-X mixed exciton in indirect band gap (In,Al)As/AlAs quantum dots

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Microsecond Lifetime of Exciton Spin Polarization in (In,Al)As/AlAs Quantum Dots

Mg

The Hg isoelectronic defect in ZnO

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Exciton states in shallow ZnSe/(Zn,Mg)Se quantum wells: Interaction of confined and continuum electron and hole states

Te quantum well. The spin-flip scattering is characterized by its dependence on the incident and scattered light polarization as well as on the magnetic field strength and orientation. Model schemes of electric-dipole allowed spin-flip Raman processes in the exciton complexes are compared to the experimental observations, from which we find that lowering of the exciton symmetry, time of carrier spin relaxation, and mixing between electron states and, respectively, light- and heavy-hole states play an essential role in the scattering. At the exciton resonance, anisotropic exchange interaction induces heavy-hole spin-flip scattering, while acoustic phonon interaction is mainly responsible for the electron spin-flip. In resonance with the positively and negatively charged excitons, anisotropic electron-hole exchange as well as mixed electron states allow spin-flip scattering. Variations in the resonant excitation energy and lattice temperature demonstrate that localization of resident electrons and holes controls the Raman process probability and is also responsible for symmetry reduction. We show that the intensity of the electron spin-flip scattering is strongly affected by the lifetime of the exciton complex and in tilted magnetic fields by the angular dependence of the anisotropic electron-hole exchange interaction.

Uniaxial stress and Zeeman spectroscopy of the 3.324 eV Ge-related photoluminescence in ZnO

The band structure of type-I (In,Al)As/AlAs quantum dots with band gap energy exceeding 1.63 eV is indirect in momentum space, leading to long-lived exciton states with potential applications in quantum information. Optical access to these excitons is provided by mixing of the

Spin-flip Raman scattering of the resident electron in singly charged (In,Ga)As/GaAs quantum dot ensembles

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Dynamical control of Mn spin-system cooling by photogenerated carriers in a (Zn,Mn)Se/BeTe heterostructure

- and X-conduction band valleys, from which control of their spin states can be gained. This access is used here for studying the exciton spin-level structure by resonant spin-flip Raman scattering, allowing us to accurately measure the anisotropic hole and isotropic electron