Dynamic nuclear self-polarization of III–V semiconductors

III–V semiconductors exhibit dynamic nuclear self-polarization (DYNASP) owing to the contact hyperfine interaction (HFI) between optically excited conduction electrons and lattice nuclei. In the self-polarization process at a low temperature, electron spin state and the nuclear polarization (magnetization) exchange a positive feedback, increasing energy splitting of the conduction electron states, thereby a large nuclear polarization. This phenomenon was theoretically predicted previously for conduction electrons excited linearly and elliptically polarized light. The polarization of the conduction electrons was represented by a parameter α in a formula for nuclear polarization (Eq. (9) in Ref. [1]); however, the effect of external magnetic fields on the nuclear polarization was not considered. Therefore, this study introduces this effect by further extending the previous studies. Herein, α ′ represents the combination of the effects of elliptically polarized electrons and an external magnetic field, which is used in the equations presented in previous studies. When α ′ = 0, a large nuclear polarization is obtained below critical temperature T c , but no polarization occurs above T c . When α ′ > 0, the nuclear polarization is enhanced above T c . Below T c , the nuclear polarization follows a hysteresis curve when α ′ is partially manipulated by adjusting the degree of the polarization of the exciting laser.