Optical band edge of diluted magnetic semiconductors
Optical band edge of diluted magnetic semiconductors
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DOI：
10.1103/physrevb.70.035207
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发表时间：
2004-07
影响因子：
3.7
通讯作者：
Masao Takahashi
中科院分区：
文献类型：
--
作者：
Masao Takahashi
本文应用动力学相干势近似，对稀磁半导体（DMS）的光学带边行为进行了理论研究。对于-型DMS，本研究揭示了交换作用引起的自旋分裂与平均磁化强度之间的线性关系在不同的α值下广泛成立。然而，该比值并不与交换积分一致，而是取决于交换强度和带偏移。此外，本研究还揭示了在低稀释度下，光学带边不是存在于杂质带的带边，而是存在于主体带的底部附近。光学带边的行为，如果交换相互作用是铁磁性的，虽然反铁磁性交换相互作用实际上在Mn网站上运行。我们的结论是，自旋相关的杂质带和主机带之间的载流子状态的移动伴随着磁化强度的变化导致的异常行为的光学带边（交换积分的表观符号的反转），在磁反射测量报告。
Applying the dynamical coherent potential approximation to a simple model, we have theoretically studied the behavior of the optical band edge in diluted magnetic semiconductors (DMS). For-type DMS, the present study reveals that the linear relationship between spin splitting due to the exchange interactionand averaged magnetizationwidely holds for different values of. The ratio,, however, does not agree with the exchange integral, but depends on both the exchange strength and the band offset. Furthermore, the present study reveals that in the low dilution of, the optical band edge exists not at the band edge of the impurity band but near the bottom of the host band. The optical band edge behaves as if the exchange interaction is ferromagnetic although the antiferromagnetic exchange interaction actually operates at the Mn site. We conclude that the spin-dependent shift of the carrier states between the impurity band and the host band accompanied by the change of magnetization causes the anomalous behavior of the optical band edge (the reversal of the apparent sign of the exchange integral) that was reported in the magnetoreflection measurement of.