TY - JOUR

T1 - Optical Orientation of Excitons in a Longitudinal Magnetic Field in Indirect-Band-Gap (In,Al)As/AlAs Quantum Dots with Type-I Band Alignment

AU - Shamirzaev, T S

AU - Shumilin, A V

AU - Smirnov, D S

AU - Kudlacik, D

AU - Nekrasov, S V

AU - Kusrayev, Yu G

AU - Yakovlev, D R

AU - Bayer, M

N1 - Funding: The work of D.K., D.R.Y., and M.B. was supported by Deutsche Forschungsgemeinschaft via project No. 409810106. D.S.S. thanks Foundation for the Advancement of Theoretical Physics and Mathematics “BASIS.” The development of the analytical theoretical model of QD blockade by D.S.S. was supported by Russian Science Foundation, grant No. 21-72-10035. All experimental activities conducted by T.S.S., including sample growth, microscopy, and investigation of the energy level spectra and magneto-optical properties, as well as exciton recombination and spin dynamics, were supported by a grant of Russian Science Foundation (No. 22-12-00022). The numerical calculations of luminescence polarization and intensity conducted by A.V.S. were supported by a grant of Russian Science Foundation (No. 22-12-00125).

PY - 2023/2/14

Y1 - 2023/2/14

N2 - Exciton recombination and spin dynamics in (In,Al)As/AlAs quantum dots (QDs) with indirect band gap and type-I band alignment were studied. The negligible (less than 0.2 μeV) value of the anisotropic exchange interaction in these QDs prevents the mixing of the excitonic basis states and makes the formation of spin-polarized bright excitons possible under quasi-resonant, circularly polarized excitation. The recombination and spin dynamics of excitons are controlled by the hyperfine interaction between the electron and nuclear spins. A QD blockade by dark excitons was observed in the magnetic field, that eliminates the impact of nuclear spin fluctuations. A kinetic model which accounts for the population dynamics of the bright and dark exciton states as well as for the spin dynamics was developed to quantitatively describe the experimental data.

AB - Exciton recombination and spin dynamics in (In,Al)As/AlAs quantum dots (QDs) with indirect band gap and type-I band alignment were studied. The negligible (less than 0.2 μeV) value of the anisotropic exchange interaction in these QDs prevents the mixing of the excitonic basis states and makes the formation of spin-polarized bright excitons possible under quasi-resonant, circularly polarized excitation. The recombination and spin dynamics of excitons are controlled by the hyperfine interaction between the electron and nuclear spins. A QD blockade by dark excitons was observed in the magnetic field, that eliminates the impact of nuclear spin fluctuations. A kinetic model which accounts for the population dynamics of the bright and dark exciton states as well as for the spin dynamics was developed to quantitatively describe the experimental data.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85149028050&origin=inward&txGid=e2586b15d91efc10682c833c16d80fb4

UR - http://arxiv.org/abs/2301.11138

UR - https://www.mendeley.com/catalogue/07e6ec97-17b2-3812-9cb1-ffa561547f51/

U2 - 10.3390/nano13040729

DO - 10.3390/nano13040729

M3 - Article

C2 - 36839097

VL - 13

JO - Nanomaterials

JF - Nanomaterials

SN - 2079-4991

IS - 4

M1 - 729

ER -