Role of resident electrons in the manifestation of a spin polarization memory effect in Mn delta-doped GaAs heterostructures

Agradecimentos: This work was supported by the 5-100 Competitiveness Enhancement Program. The work of D.V.K. has been supported by the Ministry of Science and Higher Education of Russian Federation under the State Assignment No. 0729- 2020-0058. The work of K.S.K. has been supported by the President of Russian Federation grant for young researchers Grant No. MK-2740.2021.1.2. F.I. acknowledges the CNPq (Grant No. 432882/2018-9) for financial support. M.A.G.B. acknowledges FAPEMIG Grant No. CEX-APQ-00753-18. M.V.D. and M.V.V. acknowledge the grant of the President of the Russian Federation, Grant No. MD-1708.2019.2. The authors are grateful to Dr. V. Ya. Aleshkin (Institute for Physics of Microstructures RAS) for providing the software package. The authors declare no conflict of interest Abstract: The GaAs/InGaAs quantum wells with a ferromagnetic delta(Mn) layer in GaAs barrier demonstrate a set of interesting spin-related phenomena originating from Mn-hole interaction. One of such phenomena is a spin-memory effect which consists of Mn spin polarization induced by interaction with vicinity spin-polarized holes generated under the exposure by short circularly polarized light pulses. Here long Mn spin relaxation time (similar to 5 ns) allows preserving the spin polarization of the entire system. In the present paper the spin-memory effect investigation was carried out by analyzing the polarization kinetics of quantum-well photoluminescence in the pump-probe technique. It was shown that the photoluminescence circular polarization degree is strongly affected by the magnetic interaction of holes with Mn atoms prepolarized by the pump pulse. In the case of antiparallel Mn and hole polarizations, magnetic interaction leads to decrease of circular polarization degree as compared with single-pulse excitation (so called Delta P effect). Interestingly, the amplitude of hole-mediated Delta P effect is strongly affected by the concentration of resident electrons in the quantum well. The latter was shown to be caused by the specific compliance with selection rules for optical transitions with the participation of unpolarized resident electrons and spin-polarized holes affected by Mn-hole interaction CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG Fechado