M. M. Afanasiev

Optical orientation and spin-dependent recombination in GaAsN alloys under continuous-wave pumping

We present a systematic theoretical study of spin-dependent recombination and its effect on optical orientation of photoelectron spins in semiconductors with deep paramagnetic centers. For this aim we generalize the Shockley-Read theory of recombination of electrons and holes through the deep centers with allowance for optically-induced spin polarization of free and bound electrons. Starting from consideration of defects with three charge states we turn to the two-charge-state model possessing nine parameters and show that it is compatible with available experimental data on undoped GaAsN alloys. In the weak- and strong-pumping limits, we derive simple analytic equations which are useful in prediction and interpretation of experimental results. Experimental and theoretical dependences of the spin-dependent recombination ratio and degree of photoluminescence circular polarization on the pumping intensity and the transverse magnetic field are compared and discussed.

Determination of strain-induced valence-band splitting in GaAsN thin films from circularly polarized photoluminescence

The paper studies the circularly polarized photoluminescence (PL) from dilute GaAsN alloys with nitrogen content of 1%–3.4%, grown on GaAs substrates. The room-temperature PL is found to consist of two bands whose splitting grows with increasing nitrogen content. The analysis of the PL circular polarization has shown that the PL bands originate from the splitting of light- and heavy-hole subbands, induced by an elastic strain in GaAsN layer. The dependence of the energy gap of unstrained GaAsN on the nitrogen content has been calculated using the measured light- and heavy-hole splittings.

Amplification of spin-filtering effect by magnetic field in GaAsN alloys

We have found that intensity

Controllable structuring of exciton-polariton condensates in cylindrical pillar microcavities

I

Ring-shaped polariton lasing in pillar microcavities

and circular polarization degree

Optical orientation of nuclei in nitrogen alloys GaAsN at room temperature

\rho

The sign of electron g-factor in GaAs1−xNx measured by using the Hanle effect

of the edge photoluminescence, excited in GaAsN alloys by circularly polarized light at room temperature, grow substantially in the longitudinal magnetic field

Controlled switching between quantum states in the exciton–polariton condensate

B

Hanle effect and spin-dependent recombination at deep centers in GaAsN

of the order of 1\,kG. This increase depends on the intensity of pumping and, in the region of weak or moderate intensities, may reach a twofold value. In two-charge-state model, which considers spin-dependent recombination of spin-oriented free electrons on deep paramagnetic centers, we included the magnetic-field suppression of spin relaxation of the electrons bound on centers. The model describes qualitatively the rise of

Persistent circular currents of exciton-polaritons in cylindrical pillar microcavities

\rho