TY - JOUR

T1 - Optical spin polarization in double charged InAs self-assembled quantum dots

AU - Kalevich, V. K.

AU - Merkulov, I. A.

AU - Shiryaev, A. Yu

AU - Kavokin, K. V.

AU - Ikezawa, M.

AU - Okuno, T.

AU - Brunkov, P. N.

AU - Zhukov, A. E.

AU - Ustinov, V. M.

AU - Masumoto, Y.

PY - 2005/2/1

Y1 - 2005/2/1

N2 - The work is an experimental study of optical spin polarization in InAs/GaAs quantum dots (QDs) with 2 resident electrons or holes. A capture of a photo-generated electron-hole pair into such a QD creates a negative or positive tetron (double-charged exciton). Spin polarization was registered by the circular polarization of the QD photoluminescence (PL). The spin state was found to differ radically in the dots with opposite in sign charge. Particularly, under excitation in a GaAs barrier, the ground state PL polarization is negative (relative to the polarization of an exciting light) in the negatively charged QDs and positive in the positively charged QDs. With increasing excitation intensity, the negative polarization rises from zero up to a saturation level, while the positive polarization decreases. The negative polarization increases in weak magnetic fields applied in Faraday geometry, but strong fields suppress it. The positive polarization always increases as a function of magnetic field. We propose a theoretical model that qualitatively explains the experimental results.

AB - The work is an experimental study of optical spin polarization in InAs/GaAs quantum dots (QDs) with 2 resident electrons or holes. A capture of a photo-generated electron-hole pair into such a QD creates a negative or positive tetron (double-charged exciton). Spin polarization was registered by the circular polarization of the QD photoluminescence (PL). The spin state was found to differ radically in the dots with opposite in sign charge. Particularly, under excitation in a GaAs barrier, the ground state PL polarization is negative (relative to the polarization of an exciting light) in the negatively charged QDs and positive in the positively charged QDs. With increasing excitation intensity, the negative polarization rises from zero up to a saturation level, while the positive polarization decreases. The negative polarization increases in weak magnetic fields applied in Faraday geometry, but strong fields suppress it. The positive polarization always increases as a function of magnetic field. We propose a theoretical model that qualitatively explains the experimental results.

UR - http://www.scopus.com/inward/record.url?scp=25444483856&partnerID=8YFLogxK

U2 - 10.1002/pssa.200460324

DO - 10.1002/pssa.200460324

M3 - Article

AN - SCOPUS:25444483856

VL - 202

SP - 387

EP - 391

JO - Physica Status Solidi (A) Applications and Materials Science

JF - Physica Status Solidi (A) Applications and Materials Science

SN - 1862-6300

IS - 3

ER -