Microsecond Lifetime of Exciton Spin Polarization in (In,Al)As/AlAs Quantum Dots
T. S. Shamirzaev1, D. Dunker2, J. Debus2, D. R. Yakovlev2,3, K. S. Zhuravlev1, M. Bayer3
a:2:{s:4:"TEXT";s:398:"1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 13, Novosibirsk, 630090 Russia
2Experimentelle Physik 2, Technische Universit¨at Dortmund, Dortmund, 44221 Germany
3Ioffe Physical Technical Institute, Russian Academy of Sciences, ul. Politekhnicheskaya 26, St. Petersburg, 194021 Russia";s:4:"TYPE";s:4:"html";}
Keywords: quantum dots, exciton, spin relaxation
Subsection: SEMICONDUCTOR NANOHETEROSTRUCTURES FOR SPINTRONICS
Abstract
The time of spin relaxation of excitons in (In,Al)As/AlAs quantum dots with an indirect bandgap and type-I band alignment is determined by measuring the dynamics of photoluminescence circular polarization induced by a magnetic field B. The spin relaxation time τS increases with decreasing magnetic field in proportion to B−5; its value is ~40 µs in a magnetic field of 6 T at a temperature of 1.8 K. As the temperature T increases in a magnetic field of 7T, the value of τS decreases as T−1.1. The character of the dependences of τS on the magnetic field and temperature evidences that spin relaxation of excitons is provided by a process with participation of one acoustic phonon.
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