Exciton localization by magnetic polarons and alloy fluctuations in the diluted magnetic semiconductor Cd1-xMnxTe.
Exciton localization by magnetic polarons and alloy fluctuations in the diluted magnetic semiconductor Cd1-xMnxTe.
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稀释磁性半导体 Cd1-xMnxTe 中磁极化子和合金涨落引起的激子局域化。
DOI：
10.1103/physrevb.51.4858
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
V. Aguekian
中科院分区：
文献类型：
--
作者：
S. Takeyama;S. Adachi;Y. Takagi;V. Aguekian
在4.2 ~ 60 K的温度下，测量了稀磁半导体合金Cd 1− x Mn x Te（0.1< x< 0.35）的光致发光。详细的线形分析的激子发光进行显示的峰位置的温度依赖性，积分强度，线加宽，和不对称的光谱形状。L2线的发光强度在低温下突然增长，这归因于激子磁极化子（EMP's）或合金势涨落（APF's）引起的激子局域化。只有尽可能低的激光功率激发才能使我们观察到由前者引起的效应。特征线的形状，特别是发光线的不对称性，根据一种类型的本地化：EMP的或APF的进行了讨论。我们已经确定了从EMP的和APF的本地化的结合能，作为锰合金浓度的函数。结果与现有的理论进行了比较。发现EMP能量依赖于Mn孤立局域自旋数的立方，当x> 0.20时EMP几乎不能形成，当0.05< x< 0.1时EMP最稳定.我们发现，由于APF的主要本地化是不必要的EMP的形成，但自旋涨落本地化的可能性仍然存在。
Photoluminescence was measured on the diluted magnetic semiconductor alloys Cd 1− x Mn x Te with 0.1< x< 0.35, at temperatures between 4.2 and 60 K. Detailed line-shape analysis of the exciton luminescence is carried out to show the temperature dependence of peak positions, integrated intensities, line broadening, and asymmetry of the spectral shape. The luminescence intensity of the so-called L 2 line grows abruptly at low temperatures, and is attributed to exciton localization caused either by exciton magnetic polarons (EMP’s) or alloy potential fluctuations (APF’s). Only the lowest possible laser-power excitation enables us to observe the effect caused by the former. The characteristic line shape, especially the asymmetry of the luminescence line, is discussed in accordance with a type of localization: EMP’s or APF’s. We have determined the binding energies of localization from EMP’s and APF’s, as a function of Mn alloy concentrations. The results are compared with existing theories. It is found that the EMP energy depends on the cube of the number of Mn isolated local spins, and EMP formation is barely realized at x> 0.20, and most stable at 0.05< x< 0.1. We found that the primary localization due to APF’s is not necessary for EMP formation, but that the possibility of spin-fluctuation localization still remains.