磁性イオンを希薄ドープした半導体量子ナノワイヤ中のスピン制御(<特集>半導体エレクトロニクス)

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We have studied anisotropic exchange interaction in (CdTe)_<0.5>(Cd_<0.75>Mn_<0.25>Te)_<0.5> tilted superlattices fabricated by fractional monolayer growth onto a 1° off vicinal surface of Cd_<0.74>Mg_<0.26>Te(001). The (CdTe)_<0.5>(Cdo.7sMno.25Te)_<0.5> tilted superlattices have been confirmed by polarized photoluminescence to be equivalent to compositionally modulated quantum wires consisting of CdTe-rich and Cdo.75Mno.2sTe-rich wires. The Stokes shift for the CdTe-rich wires is remarkable at less than 10K. The large Stokes shift is due to exciton-magnetic polaron formation and non-magnetic localization. The exciton magnetic polaron formation is a result of the exchange interaction between excitons and Mn ions. The exchange interaction causes the large Zeeman shift of the CdTe-rich wires. The Zeeman shift depends on the direction of the magnetic field in the (001) plane; the Zeeman shift in the magnetic field parallel to the wire direction is smaller than that in the perpendicular field. We demonstrate reorientation of hole spins in the parallel magnetic field by polarized magneto-photoluminescence measurements. The reorientation of the hole spins causes the valence-band mixing, which results in the small Zeeman shift: in the parallel magnetic field.
社団法人日本材料学会の論文
2004-12-15