Nanoscale ferromagnetism in nonmagnetic doped semiconductors
Nanoscale ferromagnetism in nonmagnetic doped semiconductors
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DOI：
10.1103/physrevb.76.161202
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发表时间：
2007-05
影响因子：
3.7
通讯作者：
E. Nielsen;R. Bhatt
中科院分区：
文献类型：
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作者：
E. Nielsen;R. Bhatt
虽然在相对高温下的铁磁性在稀磁半导体中被观察到，如${\martrm {Ga}}_{1\ensuremath{-}x}{\martrm {Mn}}_{x}\martrm {As}$，没有磁性离子的掺杂半导体没有表现出铁磁性的证据。使用一个广义的无序哈伯德模型，旨在表征半导体中的类氢中心，我们发现，这样的系统也可能表现出铁磁基态，至少在纳米尺度上。这是最清楚地发现，在一个制度无法进入散装系统，但可达到量子点以及异质结构。我们提出的数值计算结果表明，在晶格和位置无序系统中的高自旋基态的发生。我们研究了如何磁相位的影响，真实的掺杂半导体的特性，如位置的障碍和电子空穴的不对称性。
While ferromagnetism at relatively high temperatures is seen in diluted magnetic semiconductors such as ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$, doped semiconductors without magnetic ions have not shown evidence for ferromagnetism. Using a generalized disordered Hubbard model designed to characterize hydrogenic centers in semiconductors, we find that such systems may also exhibit a ferromagnetic ground state, at least on the nanoscale. This is found most clearly in a regime inaccessible to bulk systems, but attainable in quantum dots as well as heterostructures. We present numerical results demonstrating the occurrence of high spin ground states in both lattice and positionally disordered systems. We examine how the magnetic phases are affected by characteristics of real doped semiconductors, such as positional disorder and electron-hole asymmetry.