The photoexcited spin-aligned state of high-density exciton magnetic polarons and the effect of magnetic field in semimagnetic semiconductor Cd(0.8)Mn(0.2)Te.
In Cd(0.8)Mn(0.2)Te, nonlinear  photoluminescence (PL) appears only when localized excitons are selectively excited to high-density states. Here, the effect of a magnetic field is compared between nonlinear PL and PL due to localized magnetic polarons. Nonlinear PL shows a shift towards lower energy under an applied magnetic field, whereas PL of a localized magnetic polaron band shows a slight shift towards higher energy. The experimental results support the hypothesis that the origin of the nonlinear PL is a spin-aligned state of high-density exciton magnetic polarons. In the spin-aligned state, most spins of electrons (holes) in many magnetic polarons point in the same direction. In this new high-density photoexcited state, the s, p-d exchange interaction between photoexcited electrons (holes) and magnetic ions plays an important role.
Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo, 152-8551, Japan. katayamakouichi@gmail.com
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Katayama
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Miyajima
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M
Ashida
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Itoh