Coherent potential approach to exchange-induced band splitting in diluted magnetic semiconductors under a saturating magnetic field
Coherent potential approach to exchange-induced band splitting in diluted magnetic semiconductors under a saturating magnetic field
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饱和磁场下稀磁半导体中交换引起的能带分裂的相干势方法
DOI：
10.1088/0953-8984/13/14/316
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Masao Takahashi
中科院分区：
文献类型：
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作者：
Masao Takahashi
将相干势近似 (CPA) 应用于描述具有强外加磁场的 AII1-xMnxBVI 型稀磁半导体 (DMS) 中的磁性和化学无序的模型，我们计算了带边能量偏移作为 Mn 浓度 (x) 的函数。系统地研究了DMS中能带偏移和交换相互作用对扩展载流子状态的影响。在 Cd1-xMnxS 中观察到的 p-d 交换相互作用的明显增强可以很好地解释为多重散射效应，这对于无序系统中的小 x 非常重要。主要来源不是 Mn 位点处较大的吸引化学势，而是相对于带宽的较大交换能。
Applying the coherent potential approximation (CPA) to a model which describes magnetic and chemical disorder in an AII1-xMnxBVI-type diluted magnetic semiconductor (DMS) with a strong applied magnetic field, we calculate the band-edge energy shift as a function of the Mn concentration (x). The effects of the band offset and exchange interaction on the extended carrier state in a DMS are studied systematically. The apparent enhancement of the p-d exchange interaction which is observed in Cd1-xMnxS is explained well as a multiple-scattering effect which is significant for small x in disordered systems. The dominant origin is not a large attractive chemical potential at the Mn site, but a large exchange energy relative to the bandwidth.