Spin Transport of Excitons

Spin transport of excitons.

We report on observation of the spin transport of spatially indirect excitons in GaAs/AlGaAs coupled quantum wells (CQW). Exciton spin transport over substantial distances, up to several micrometers in the present work, is achieved due to orders of magnitude enhancement of the exciton spin relaxation time in CQW with respect to conventional quantum wells.

Effective Hamiltonian for Excitons with Spin Degrees of Freedom

Starting from the conventional electron-hole Hamiltonian Heh, we derive an effective Hamiltonian H̃1s for 1s excitons with spin degrees of freedom. The Hamiltonian describes optical processes close to the exciton resonance for the case of weak excitation. We show that straightforward bosonization of Heh does not give the correct form of H̃1s, which we obtain by a projection onto the subspace span...

Electron-spin beat susceptibility of excitons in semiconductor quantum wells.

Recent time-resolved differential transmission and Faraday rotation measurements of long-lived electron-spin coherence in quantum wells displayed intriguing parametric dependencies. For their understanding we formulate a microscopic theory of the optical response of a gas of optically incoherent excitons whose constituent electrons retain spin coherence, under a weak magnetic field applied in t...

Spin polarization of excitons in organic multiferroic composites

Recently, the discovery of room temperature magnetoelectricity in organic charge transfer complexes has reignited interest in the multiferroic field. The solution processed, large-area and low cost organic semiconductor materials offer new possibilities for the functional all organic multiferroic devices. Here we report the spin polarization of excitons and charge transfer states in organic cha...

Spin dynamics of isoelectronic bound excitons in ZnO