Phonon impact on the dynamics of resonantly excited and hot excitons in diluted magnetic semiconductors

Abstract

Phonons are well known to be the main mechanism for the coupling between bright and dark excitons in nonmagnetic semiconductors. Here, we investigate diluted magnetic semiconductors where this process is in direct competition with the scattering at localized magnetic impurities. To this end, a recently developed quantum kinetic description of the exciton spin dynamics in diluted magnetic semiconductor quantum wells is extended by the scattering with longitudinal acoustic phonons. A strong phonon impact is found in the redistribution of exciton momenta on the exciton parabola that becomes especially prominent for high temperatures and exciton distributions further away from the exciton resonance which are optically dark. Despite their impact on the energetic redistribution, acoustic phonons virtually do not affected the exciton spin dynamics as the exciton-impurity interaction always dominates. Furthermore, it turns out that the exciton spin lifetime increases by roughly one order of magnitude for nonequilibrium hot exciton distributions and, in addition, pronounced quantum kinetic signatures in the exciton spin dynamics appearing after resonant optical excitation are drastically reduced.

13 pages, 6 figures

References in corpus (6)

• Ultrafast demagnetization in the sp-d model: a theoretical study
• Influence of non-magnetic impurity scattering on the spin dynamics in diluted magnetic semiconductors
• Ultrafast spin dynamics in II-VI diluted magnetic semiconductors with spin-orbit interaction
• Quantum kinetic equations for the ultrafast spin dynamics of excitons in diluted magnetic semiconductor quantum wells after optical excitation
• Trend reversal in the magnetic-field dependence of exciton spin-transfer rates in diluted magnetic semiconductors due to non-Markovian dynamics
• Many-body correlations brought to light in absorption spectra of diluted magnetic semiconductors

Cited by in corpus (3)

• Spin dynamics of hot excitons in diluted magnetic semiconductors with spin-orbit interaction
• Role of excited states in the dynamics of excitons and their spins in diluted magnetic semiconductors
• Origins of overshoots in the exciton spin dynamics in semiconductors