Raman Investigation of the Mn2+–Mn2+ Interaction in Semimagnetic Semiconductor Quantum Wells
Raman Investigation of the Mn2+–Mn2+ Interaction in Semimagnetic Semiconductor Quantum Wells
复制标题
半磁半导体量子阱中 Mn2+-Mn2+ 相互作用的拉曼研究
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
I. Merkulov
中科院分区：
文献类型：
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作者：
J. Stühler;G. Schaack;M. Dahl;A. Waag;G. Landwehr;K. Kavokin;I. Merkulov
在锰基半磁半导体中，孤立的反铁磁耦合的Mn2+离子对具有一系列的能级，这些能级的分离由它们的近邻交换相互作用决定。在含有不同宽度和不同锰浓度的半磁量子阱(CD1-xMnxTe)的Cd1-xMnxTe/Cd1-yMgyTe量子井结构中，观察到了Th=0基态和磁分裂=1能级之间的拉曼跃迁。THs=0=1，M=0跃迁的拉曼频移与Mn的浓度有不可忽略的依赖关系，这是由于Mn2+对与更远的近邻相互作用的结果。测定了Cd1-xMnxTe的最近邻交换常数JnN=-(6.11±0.15)K。在此基础上，给出了一个散射机制的模型，由于载流子自旋与局域Mn2+离子之间的强交换作用，能带边态在散射过程中充当中间态。量子阱中的限制和局域效应对Mn2+对拉曼信号的强度起着决定性的作用，它们产生了强烈的载流子波函数梯度。
Isolated pairs of antiferromagnetically coupled Mn2+ ions in Mn-based semimagnetic semiconductors possess a series of energy levels whose separation is determined by their nearest-neighbour exchange interaction. Raman transitions were observed between theS=0 ground state and the magnetically splitS=1 levels of these pairs in Cd1-xMnxTe/Cd1-yMgyTe quantum well structures comprising semimagnetic quantum wells (Cd1-xMnxTe) of different well widths and Mn concentrations. The Raman shift of theS=0S=1,M=0 transition shows a non-negligible dependence on the Mn concentration, which is interpreted as an effect due to interaction of the Mn2+ pair with more distant neighbours. A nearest-neighbour exchange constantJNN=-(6.11±0.15) K for Cd1-xMnxTe is determined. Further, a model is presented for the scattering mechanism, where band-edge states act as intermediate states in the scattering process owing to the strong exchange interaction between the carrier spin and the localized Mn2+ ions. Confinement and localization effects in the quantum well, which produce strong gradients of the carrier wavefunction, play a decisive role for the intensity of the Mn2+ pair Raman signals.