講演情報
[21a-C501-9]Nuclear Spin Dynamics of Bulk AlGaAs studied by Time-Resolved Kerr Rotation Technique
〇Andong Shen1, Kaji Reina1, Uemura Tetsuya2, Adachi Satoru1 (1.Grad. Sch. Eng., Hokkaido Univ., 2.Grad. Sch. IST, Hokkaido Univ.)
キーワード：
nuclear spin polarization、bulk semiconductor
The formation of nuclear magnetic fields (BN) in n-doped AlGaAs bulk samples under an oblique magnetic field (Bext) is investigated in this paper. Because of the uniform distribution of electron wave functions, bulk semiconductors are thought to have poor localization and restricted dynamic nuclear polarization compared to semiconductor nanostructures. The study, however, suggests a large BN of up to 1.2 T, with a formation timescale of around 3,000 seconds. To compare the phenomenon, three samples with various Al concentrations (x=0, 0.05, and 0.15) are used in the experiment. For observation, time-resolved Kerr rotation measurements and all-optical nuclear magnetic resonance techniques are used. The study discovers two-stage formation dynamics with rapid and slow formation parts, implying a possible role of slow nuclear diffusion. Furthermore, slow depolarization dynamics are found, indicating a relaxing process associated with nuclear quadrupole splitting. With increasing Al concentration, the amplitude of BN and depolarization time rise, demonstrating the profound influence of nuclear quadrupole interaction on the creation and depolarization dynamics of BN.