Localization of electronic eigenstates and spin waves in diluted magnetic semiconductors at low carrier densities
Localization of electronic eigenstates and spin waves in diluted magnetic semiconductors at low carrier densities
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DOI：
10.1002/pssb.200404782
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发表时间：
2004-07
期刊：
影响因子：
--
通讯作者：
M. Berciu;R. Bhatt
中科院分区：
文献类型：
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作者：
M. Berciu;R. Bhatt
使用平均场和随机相位近似，我们对有限尺寸系统进行数值模拟，以研究无序对具有电子（费米子）和磁自由度的原型无序系统的电子态和集体磁（自旋波）激发的性质（局部或扩展）的影响。我们使用一个简单的杂质模型，适用于低载流子浓度、低于或接近金属-绝缘体转变的稀磁半导体。在我们的模型中，从一开始就考虑了磁性掺杂剂的位置无序。我们发现，增强的无序意味着磁特性的显着不均匀性，导致局部电子态以及局部集体磁激发的出现。因此，在低掺杂剂和载流子密度下，掺杂剂的位置无序会显着影响此类材料的输运和磁性能。 （© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
Using mean‐field and random‐phase approximations, we perform numerical simulations on finite‐size systems to investigate the effects of disorder on the nature (localized or extended ) of both electronic states and collective magnetic (spin‐wave) excitations for a prototypical disordered system with both electronic (fermionic) and magnetic degrees of freedom. We use a simple impurity model appropriate for dilute magnetic semiconductors at low charge carrier concentrations, below and near the metal‐insulator transition. In our model, the positional disorder of the magnetic dopants is taken into account at the outset. We find that enhanced disorder implies significant inhomogeneity in magnetic properties, leading to appearance of localized electron states as well as localized collective magnetic excitations. As a result, positional disorder of the dopants can significantly influence transport and magnetic properties in such materials at low dopant and carrier densities. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)