Single-site approximation for the s-f model in ferromagnetic semiconductors.
Single-site approximation for the s-f model in ferromagnetic semiconductors.
复制标题
铁磁半导体中 s-f 模型的单点近似。
DOI：
10.1103/physrevb.54.11298
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Kazuhiro Mitsui
中科院分区：
文献类型：
--
作者：
Masao Takahashi;Kazuhiro Mitsui
将相干势近似应用于S-f模型，从理论上研究了铁磁半导体中的传导电子态。为了考虑铁磁温度下的多重散射，我们首先推导了有效介质中单个{italf}自旋的{italf}自旋的{italt}-{italf}交换作用的矩阵元，其中传导电子受到复势，根据其自旋的取向，{sigma}{sub{up_arrow}}或{sigma}{sub{down_arrow}}。利用涨落自旋的平均场理论，研究了不同的态密度随温度的变化规律。这里，{italIS}是交换相互作用能，{italW}是导带的带宽。在EuO和EUS中实验观察到的光学吸收边的反常红移和电子自旋极化与温度的关系，可以在这个近似下一致地解释。{版权所有}{1996年美国物理学会。}
The conduction-electron state in a ferromagnetic semiconductor is studied theoretically by applying the coherent-potential approximation to the {ital s}-{ital f} model. In order to consider multiple scattering at ferromagnetic temperatures, we first derive the {ital t}-matrix elements of the {ital s}-{ital f} exchange interaction for a single {ital f} spin embedded in the effective medium, where a conduction electron is subjected to complex potential, {Sigma}{sub {up_arrow}} or {Sigma}{sub {down_arrow}}, according to the orientation of its spin. Using the mean-field theory for fluctuating {ital f} spins, the variation of the density of states with temperature is investigated for various values of {ital IS}/{ital W}. Here {ital IS} is the exchange interaction energy and {ital W} is the bandwidth of the conduction band. The anomalous redshift of the optical-absorption edge and the temperature dependence of the electron-spin polarization, experimentally observed in EuO and EuS, can be explained consistently within this approximation. {copyright} {ital 1996 The American Physical Society.}