Dynamic nuclear self-polarization of Ⅲ–Ⅴsemiconductors  

作　　者：M. Koizumi J. Goto S. Matsuki 

机构地区：[1]Nuclear Science and Engineering Center (concurrently: Integrated Support Center for Nuclear Nonproliferation and NuclearSecurity), Japan Atomic Energy Agency, Shirakata 2-4, Toukai-mura, Naka, Ibaraki 319-1195, Japan [2]Institute for Research Promotion, Niigata University, Asahimachi-dori 1-757, Niigata, Niigata 951-8510, Japan [3]Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan

出　　处：《Journal of Semiconductors》2018年第8期1-5,共5页半导体学报（英文版）

基　　金：supported by the Grant-in-Aid for Scientific Research(C)of Japan Society for the Promotion of Science(JSPS)(Nos.21540307,26400298)

摘　　要：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 Tc, but no polarization occurs above Tc. When α′ > 0, the nuclear polarization is enhanced above Tc. Below Tc, the nuclear polarization follows a hysteresis curve when α′ is partially manipulated by adjusting the degree of the polarization of the exciting laser.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.

关 键 词：nuclear polarization optical polarization INP overhauser Ⅲ–Ⅴ semiconductor 

分 类 号：TN304.23[电子电信—物理电子学]