Spin‐flip quenching in trion state mediated by optical phonons in a single quantum dot

Abstract

AbstractHigh degree of preservation of spin states mediated by optical phonons is demonstrated with a positive trion state in a single quantum dot. At the optical phonon resonance, suppression of spin relaxation is clearly identified as dip structures in photoluminescence excitation spectra under cross‐circularly polarize detection with respect to a pumping. As a result, distinguishably high degree of circular polarization up to ∼0.85 is achieved in the absence of external magnetic field, which is not the case for neutral excitons with finite fine structure splitting. The absence of continuum states plays a crucial role for this observation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)