- 著者
- Gerlovin I. Ya. Dolgikh Yu. K. Eliseev S. A. Ovsyankin V. V. Efimov Yu. P. Petrov V. V. Ignatiev I. V. Kozin I. E. Masumoto Y.
- 出版者
- American Physical Society
- 雑誌
- Physical review B (ISSN:10980121)
- 巻号頁・発行日
- vol.65, no.3, pp.035317, 2002-01
- 被引用文献数
- 21 17
Picosecond kinetics of polarized resonant photoluminescence (PL) of HH excitons in the GaAs/AlGaAs superlattices is studied in an external magnetic field. The measurements were made in real time using a streak camera. For the magnetic field aligned along the heterostructure growth direction, the resonant PL exhibits oscillations in the degree of linear polarization. The oscillations are ascribed to quantum beats between sublevels of the optically active excitonic doublet split by the magnetic field. For the magnetic field aligned along the plane of the layers, the resonant PL is found to exhibit oscillations in circular polarization. These oscillations are related to beats between states of the optically active and optically inactive excitonic doublets. Experimental dependence of the oscillation frequency on the magnetic field strength and orientation has allowed us to determine the hole and electron g factors and the electron-hole exchange energy. Dynamics of the degree of circular polarization of the PL in magnetic field is used to measure the energy relaxation rate of the exciton spin states. In the magnetic field exceeding 1 T, the energy relaxation rate is shown to be magnetic-field independent and equal (1±0.2)×1010 s-1. This value is found to be much smaller than the spin phase relaxation rate determined from decay of the quantum beats in linear polarization. Unlike the energy relaxation rate, the latter grows linearly with the field strength and equals (5±0.5)×1010 s-1 at 5 T. It is concluded that the main mechanism responsible for loss of macroscopic spin coherence is the reversible dephasing within inhomogeneously broadened system.
- 著者
- Kozin I. E. Davydov V. G. Ignatiev I. V. Kavokin A. V. Kavokin K. V. Malpuech G. Ren Hong-Wen Sugisaki M. Sugou S. Masumoto Y.
- 出版者
- American Physical Society
- 雑誌
- Physical review B (ISSN:10980121)
- 巻号頁・発行日
- vol.65, no.24, pp.241312, 2002-06
- 被引用文献数
- 61 53
Spins of resident electrons in charged quantum dots (QD’s) act as local magnets inducing the Zeeman splitting of excitons trapped into dots. This is evidenced by the observation of quantum beats in the linearly polarized time-resolved photoluminescence of a biased array of self-assembled InP QD’s. An external magnetic field is found to shorten the spin beats’ decay time keeping constant the frequency of the beats. A model using the pseudospin formalism allows one to attribute the observed quantum beats to the radiative decay of hot trions having two electrons that occupy different energy levels in a QD.
- 著者
- Yugova I. A. Gerlovin Ya. Davydov V. G. Ignatiev I. V. Kozin I. E. Ren H. W. Sugisaki M. Sugou S. Masumoto Y.
- 出版者
- American Physical Society
- 雑誌
- Physical review B (ISSN:10980121)
- 巻号頁・発行日
- vol.66, no.23, pp.235312, 2002-12
- 被引用文献数
- 37 36
The paper reports on quantum beats observed in the photoluminescence kinetics of a single layer of the InPself-assembled quantum dots in a magnetic field. It is found that the beats arise only after removal of excesscharges from the quantum dots by an external electrical bias. The quantum beats are shown to be related to theinterference of the excitonic fine-structure states split by the magnetic-field. The dependences of the beatcharacteristics on the magnetic-field strength and orientation are studied. Theoretical analysis based on a modelspin Hamiltonian has allowed us to describe adequately the shape of the oscillating component of the signal.We have determined the values of the electron g-factor components and estimated the spread and the meanvalue of the hole g factor, as well as of the electron-hole exchange splitting parameters.